Simatic - Programming with STEP7 - Process Control and ...

s 

SIMATIC 

Programming with STEP 7 

Manual 

This manual is part of the documentation 

package with the order number: 

6ES7810-4CA08-8BW0 

Edition 03/2006 

A5E00706944-01 

Preface 

Contents 

Introducing the Product and Installing 

the Software 1 

Installation 2 

Working Out the Automation Concept 3 

Basics of Designing a Program 

Structure 4 

Startup and Operation 5 

Setting Up and Editing the Project 6 

Editing Projects with Different 

Versions of STEP 7 7 

Defining Symbols 8 

Creating Blocks and Libraries 9 

Creating Logic Blocks 10 

Creating Data Blocks 11 

Parameter Assignment for Data 

Blocks 12 

Creating STL Source Files 13 

Displaying Reference Data 14 

Checking Block Consistency and 

Time Stamps as a Block Property 15 

Configuring Messages 16 

Controlling and Monitoring Variables 17 

Establishing an Online Connection 

and Making CPU Settings 18 

Downloading and Uploading 19 

Testing with the Variable Table 20 

Testing Using Program Status 21 

Testing using the Simulation Program 

(Optional Package) 22 

Diagnostics 23 

Printing and Archiving 24 

Working with M7 Programmable 

Control Systems 25 

Tips and Tricks 26 

Appendix 

Index 

A

Safety Guidelines 

This manual contains notices you have to observe in order to ensure your personal safety, as well as to 

prevent damage to property. The notices referring to your personal safety are highlighted in the manual 

by a safety alert symbol, notices referring to property damage only have no safety alert symbol. The 

notices shown below are graded according to the degree of danger. 

! 

! 

! 

Danger 

indicates that death or severe personal injury will result if proper precautions are not taken. 

Warning 

indicates that death or severe personal injury may result if proper precautions are not taken. 

Caution 

with a safety alert symbol indicates that minor personal injury can result if proper precautions are not 

taken. 

Caution 

without a safety alert symbol indicates that property damage can result if proper precautions are not 

taken. 

Qualified Personnel 

Prescribed Usage 

Notice 

indicates that an unintended result or situation can occur if the corresponding notice is not taken into 

account. 

If more than one degree of danger is present, the warning notice representing the highest degree of 

danger will be used. A notice warning of injury to persons with a safety alert symbol may also include a 

warning relating to property damage. 

The device/system may only be set up and used in conjunction with this documentation. Commissioning 

and operation of a device/system may only be performed by qualified personnel. Within the context of 

the safety notices in this documentation qualified persons are defined as persons who are authorized to 

commission, ground and label devices, systems and circuits in accordance with established safety 

practices and standards. 

Note the following: 

! 

Warning 

This device and its components may only be used for the applications described in the catalog or the 

technical description, and only in connection with devices or components from other manufacturers 

which have been approved or recommended by Siemens. 

Correct, reliable operation of the product requires proper transport, storage, positioning and assembly 

as well as careful operation and maintenance. 

Trademarks 

All names identified by ® are registered trademarks of the Siemens AG. 

The remaining trademarks in this publication may be trademarks whose use by third parties for their 

own purposes could violate the rights of the owner. 

Disclaimer of Liability 

We have reviewed the contents of this publication to ensure consistency with the hardware and 

software described. Since variance cannot be precluded entirely, we cannot guarantee full consistency. 

However, the information in this publication is reviewed regularly and any necessary corrections are 

included in subsequent editions. 

Siemens AG 

Automation and Drives 

Postfach 4848 

90437 NÜRNBERG 

GERMANY 

A5E00706944-01 

03/2006 

Copyright © Siemens AG 2006 

Technical data subject to change

Preface 

Purpose 

This manual provides a complete overview of programming with STEP 7. It is 

designed to support you when installing and commissioning the software. It 

explains how to proceed when creating programs and describes the components of 

user programs. 

The manual is intended for people who are involved in carrying out control tasks 

using STEP 7 and SIMATIC S7 automation systems. 

We recommend that you familiarize yourself with the examples in the manual 

"Working with STEP 7 V5.4, Getting Started." These examples provide an easy 

introduction to the topic "Programming with STEP 7." 

Basic Knowledge Required 

In order to understand this manual, general knowledge of automation technology is 

required. 

In addition, you must be familiar with using computers or PC-similar tools (for 

example, programming devices) with the MS Windows 2000 Professional, 

MS Windows XP Professional or MS Windows Server 2003 operating system. 

Scope of the Manual 

This manual is valid for release 5.4 of the STEP 7 programming software package. 

You can find the latest information on the service packs: 

• in the "readme.wri" file 

• in the updated STEP 7 online help. 

The topic "What's new?" in the online help offers an excellent introduction and 

overview of the newest STEP 7 innovations. 


A5E00706944-01 

iii

Preface 

STEP 7 Documentation Packages 

This manual is part of the documentation package "STEP 7 Basic Information.“ 

The following table displays an overview of the STEP 7 documentation: 

Documentation Purpose Order Number 

STEP 7 Basic Information with 

Basic information for technical 6ES7810-4CA08-8BW0 

• Working with STEP 7, 

personnel describing the methods 

Getting Started Manual 

of implementing control tasks with 

STEP 7 and the S7-300/400 

• Programming with STEP 7 

programmable controllers. 

• Configuring Hardware and 

Communication Connections, 

STEP 7 

• From S5 to S7, Converter Manual 

STEP 7 Reference with 

• Ladder Logic (LAD) / Function Block 

Diagram (FDB) / Statement List (STL) 

for S7-300/400 manuals 

• Standard and System Function 

for S7-300/400 

Volume 1 and Volume 2 

Provides reference information 

and describes the programming 

languages LAD, FBD and STL, 

and standard and system function 

extending the scope of the 

STEP 7 basic information. 

6ES7810-4CA08-8BW1 

Online Helps Purpose Order Number 

Help on STEP 7 

Basic information on 

programming and configuring 

hardware with STEP 7 in the form 

of an online help. 

Part of the STEP 7 

Standard software. 

Reference helps on AWL/KOP/FUP 

Reference help on SFBs/SFCs 

Reference help on Organization Blocks 

Context-sensitive reference 

information. 

Part of the STEP 7 

Standard software. 

iv 


A5E00706944-01

Preface 

Further Support 

If you have any technical questions, please get in touch with your Siemens 

representative or responsible agent. 

You will find your contact person at: 

http://www.siemens.com/automation/partner 

You will find a guide to the technical documentation offered for the individual 

SIMATIC Products and Systems here at: 

http://www.siemens.com/simatic-tech-doku-portal 

The online catalog and order system is found under: 

http://mall.automation.siemens.com/ 

Training Centers 

Siemens offers a number of training courses to familiarize you with the SIMATIC 

S7 automation system. Please contact your regional training center or our central 

training center in D 90327 Nuremberg, Germany for details: 

Telephone: +49 (911) 895-3200. 

Internet: http://www.sitrain.com 

Technical Support 

You can reach the Technical Support for all A&D products 

• Via the Web formula for the Support Request 

http://www.siemens.com/automation/support-request 

• Phone: + 49 180 5050 222 

• Fax: + 49 180 5050 223 

Additional information about our Technical Support can be found on the Internet 

pages http://www.siemens.com/automation/service 

Service & Support on the Internet 

In addition to our documentation, we offer our Know-how online on the internet at: 

http://www.siemens.com/automation/service&support 

where you will find the following: 

• The newsletter, which constantly provides you with up-to-date information on 

your products. 

• The right documents via our Search function in Service & Support. 

• A forum, where users and experts from all over the world exchange their 

experiences. 

• Your local representative for Automation & Drives. 

• Information on field service, repairs, spare parts and more under "Services". 


A5E00706944-01 

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Preface 

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Contents 

1 Introducing the Product and Installing the Software 1-1 

1.1 Overview of STEP 7 ......................................................................................... 1-1 

1.2 The STEP 7 Standard Package ....................................................................... 1-6 

1.3 What's New in STEP 7, Version 5.4? ............................................................. 1-11 

1.4 Extended Uses of the STEP 7 Standard Package ......................................... 1-14 

1.4.1 Engineering Tools........................................................................................... 1-15 

1.4.2 Run-Time Software......................................................................................... 1-17 

1.4.3 Human Machine Interface............................................................................... 1-19 

2 Installation 2-1 

2.1 Automation License Manager........................................................................... 2-1 

2.1.1 User Rights Through The Automation License Manager ................................. 2-1 

2.1.2 Installing the Automation License Manager...................................................... 2-4 

2.1.3 Guidelines for Handling License Keys.............................................................. 2-5 

2.2 Installing STEP 7 .............................................................................................. 2-6 

2.2.1 Installation Procedure....................................................................................... 2-8 

2.2.2 Setting the PG/PC Interface ........................................................................... 2-11 

2.3 Uninstalling STEP 7........................................................................................ 2-13 

3 Working Out the Automation Concept 3-1 

3.1 Basic Procedure for Planning an Automation Project ...................................... 3-1 

3.2 Dividing the Process into Tasks and Areas...................................................... 3-2 

3.3 Describing the Individual Functional Areas ...................................................... 3-4 

3.4 Listing Inputs, Outputs, and In/Outs ................................................................. 3-6 

3.5 Creating an I/O Diagram for the Motors ........................................................... 3-6 

3.6 Creating an I/O Diagram for the Valves............................................................ 3-7 

3.7 Establishing the Safety Requirements.............................................................. 3-8 

3.8 Describing the Required Operator Displays and Controls................................ 3-9 

3.9 Creating a Configuration Diagram .................................................................. 3-10 

4 Basics of Designing a Program Structure 4-1 

4.1 Programs in a CPU........................................................................................... 4-1 

4.2 Blocks in the User Program.............................................................................. 4-2 

4.2.1 Organization Blocks and Program Structure .................................................... 4-3 

4.2.2 Call Hierarchy in the User Program.................................................................. 4-9 

4.2.3 Block Types .................................................................................................... 4-11 

4.2.3.1 Organization Block for Cyclic Program Processing (OB1) ............................. 4-11 

4.2.3.2 Functions (FC) ................................................................................................ 4-16 

4.2.3.3 Function Blocks (FB) ...................................................................................... 4-17 

4.2.3.4 Instance Data Blocks...................................................................................... 4-20 

4.2.3.5 Shared Data Blocks (DB)................................................................................ 4-23 

4.2.3.6 System Function Blocks (SFB) and System Functions (SFC) ....................... 4-24 


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4.2.4 Organization Blocks for Interrupt-Driven Program Processing....................... 4-26 

4.2.4.1 Time-of-Day Interrupt Organization Blocks (OB10 to OB17) ......................... 4-26 

4.2.4.2 Time-Delay Interrupt Organization Blocks (OB20 to OB23)........................... 4-28 

4.2.4.3 Cyclic Interrupt Organization Blocks (OB30 to OB38).................................... 4-29 

4.2.4.4 Hardware Interrupt Organization Blocks (OB40 to OB47).............................. 4-31 

4.2.4.5 Startup Organization Blocks (OB100 / OB101 / OB102)................................ 4-32 

4.2.4.6 Background Organization Block (OB90)......................................................... 4-34 

4.2.4.7 Error Handling Organization Blocks (OB70 to OB87 / OB121 to OB122)...... 4-36 

5 Startup and Operation 5-1 

5.1 Starting STEP 7 ................................................................................................ 5-1 

5.2 Starting STEP 7 with Default Start Parameters................................................ 5-3 

5.3 Calling the Help Functions................................................................................ 5-5 

5.4 Objects and Object Hierarchy........................................................................... 5-6 

5.4.1 Project Object ................................................................................................... 5-8 

5.4.2 Library Object ................................................................................................... 5-9 

5.4.3 Station Object ................................................................................................. 5-10 

5.4.4 Programmable Module Object........................................................................ 5-12 

5.4.5 S7/M7 Program Object ................................................................................... 5-14 

5.4.6 Block Folder Object ........................................................................................ 5-16 

5.4.7 Source File Folder Object............................................................................... 5-19 

5.4.8 S7/M7 Program without a Station or CPU...................................................... 5-20 

5.5 User Interface and Operation ......................................................................... 5-21 

5.5.1 Operating Philosophy ..................................................................................... 5-21 

5.5.2 Window Arrangement ..................................................................................... 5-22 

5.5.3 Elements in Dialog Boxes............................................................................... 5-23 

5.5.4 Creating and Managing Objects ..................................................................... 5-24 

5.5.5 Selecting Objects in a Dialog Box .................................................................. 5-29 

5.5.6 Session Memory ............................................................................................. 5-30 

5.5.7 Changing the Window Arrangement............................................................... 5-31 

5.5.8 Saving and Restoring the Window Arrangement ........................................... 5-31 

5.6 Keyboard Operation........................................................................................ 5-32 

5.6.1 Key Combinations for Menu Commands........................................................ 5-32 

5.6.2 Key Combinations for Moving the Cursor....................................................... 5-34 

5.6.3 Key Combinations for Selecting Text ............................................................. 5-36 

5.6.4 Key Combinations for Access to Online Help................................................. 5-36 

5.6.5 Key Combinations for Toggling between Windows ........................................ 5-37 

6 Setting Up and Editing the Project 6-1 

6.1 Project Structure ............................................................................................... 6-1 

6.2 What You Should Know About Access Protection ........................................... 6-2 

6.3 What You Should Know About The Change Log ............................................. 6-4 

6.4 Using Foreign-Language Character Sets......................................................... 6-5 

6.5 Setting the MS Windows Language ................................................................. 6-8 

6.6 Setting Up a Project.......................................................................................... 6-9 

6.6.1 Creating a Project............................................................................................. 6-9 

6.6.2 Inserting Stations ............................................................................................ 6-11 

6.6.3 Inserting an S7/M7 Program........................................................................... 6-12 

6.7 Editing a Project.............................................................................................. 6-14 

6.7.1 Checking Projects for Software Packages Used............................................ 6-15 

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6.8 Managing Multilingual Texts ........................................................................... 6-15 

6.8.1 Types of Multilingual Texts ............................................................................. 6-17 

6.8.2 Structure of the Export File............................................................................. 6-18 

6.8.3 Managing User Texts Whose Language Font is Not Installed ....................... 6-19 

6.8.4 Information on the Log File............................................................................. 6-20 

6.8.5 Optimizing the Source for Translation ............................................................ 6-21 

6.8.6 Optimizing the Translation Process................................................................ 6-22 

6.9 Micro Memory Card (MMC) as a Data Carrier................................................ 6-23 

6.9.1 What You Should Know About Micro Memory Cards (MMC)......................... 6-23 

6.9.2 Using a Micro Memory Card as a Data Carrier .............................................. 6-25 

6.9.3 Memory Card File ........................................................................................... 6-25 

6.9.4 Storing Project Data on a Micro Memory Card (MMC)................................... 6-26 

7 Editing Projects with Different Versions of STEP 7 7-1 

7.1 Editing Version 2 Projects and Libraries........................................................... 7-1 

7.2 Expanding DP Slaves That Were Created with 

Previous Versions of STEP 7 ........................................................................... 7-1 

7.3 Editing Current Configurations with Previous Versions of STEP 7 .................. 7-3 

7.4 Appending SIMATIC PC Configurations of Previous Versions ........................ 7-4 

7.5 Displaying Modules Configured with Later STEP 7 Versions 

or Optional Packages ....................................................................................... 7-6 

8 Defining Symbols 8-1 

8.1 Absolute and Symbolic Addressing .................................................................. 8-1 

8.2 Shared and Local Symbols............................................................................... 8-3 

8.3 Displaying Shared or Local Symbols................................................................ 8-4 

8.4 Setting the Address Priority (Symbolic/Absolute)............................................. 8-5 

8.5 Symbol Table for Shared Symbols ................................................................... 8-9 

8.5.1 Structure and Components of the Symbol Table ............................................. 8-9 

8.5.2 Addresses and Data Types Permitted in the Symbol Table........................... 8-11 

8.5.3 Incomplete and Non-Unique Symbols in the Symbol Table........................... 8-12 

8.6 Entering Shared Symbols............................................................................... 8-13 

8.6.1 General Tips on Entering Symbols................................................................. 8-13 

8.6.2 Entering Single Shared Symbols in a Dialog Box .......................................... 8-14 

8.6.3 Entering Multiple Shared Symbols in the Symbol Table ................................ 8-15 

8.6.4 Using Upper and Lower Case for Symbols .................................................... 8-16 

8.6.5 Exporting and Importing Symbol Tables......................................................... 8-18 

8.6.6 File Formats for Importing/Exporting a Symbol Table .................................... 8-18 

8.6.7 Editing Areas in Symbol Tables...................................................................... 8-21 

9 Creating Blocks and Libraries 9-1 

9.1 Selecting an Editing Method............................................................................. 9-1 

9.2 Selecting the Programming Language ............................................................. 9-2 

9.2.1 Ladder Logic Programming Language (LAD)................................................... 9-4 

9.2.2 Function Block Diagram Programming Language (FBD)................................. 9-5 

9.2.3 Statement List Programming Language (STL)................................................. 9-6 

9.2.4 S7 SCL Programming Language...................................................................... 9-7 

9.2.5 S7-GRAPH Programming Language (Sequential Control) .............................. 9-8 

9.2.6 S7 HiGraph Programming Language (State Graph) ........................................ 9-9 

9.2.7 S7 CFC Programming Language ................................................................... 9-10 

9.3 Creating Blocks............................................................................................... 9-11 

9.3.1 Blocks Folder .................................................................................................. 9-11 

9.3.2 User-Defined Data Types (UDT) .................................................................... 9-12 

9.3.3 Block Properties.............................................................................................. 9-13 

9.3.4 Displaying Block Lengths................................................................................ 9-15 

9.3.5 Comparing Blocks........................................................................................... 9-16 

9.3.6 Rewiring.......................................................................................................... 9-19 


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9.3.7 Attributes for Blocks and Parameters ............................................................. 9-19 

9.4 Working with Libraries .................................................................................... 9-20 

9.4.1 Hierarchical Structure of Libraries .................................................................. 9-22 

9.4.2 Overview of the Standard Libraries ................................................................ 9-22 

10 Creating Logic Blocks 10-1 

10.1 Basics of Creating Logic Blocks ..................................................................... 10-1 

10.1.1 Structure of the Program Editor Window........................................................ 10-1 

10.1.2 Basic Procedure for Creating Logic Blocks .................................................... 10-3 

10.1.3 Default Settings for the LAD/STL/FBD Program Editor.................................. 10-4 

10.1.4 Access Rights to Blocks and Source Files ..................................................... 10-4 

10.1.5 Instructions from the Program Elements Table .............................................. 10-5 

10.2 Editing the Variable Declaration ..................................................................... 10-6 

10.2.1 Using the Variable Declaration in Logic Blocks.............................................. 10-6 

10.2.2 Interaction Between The Variable Detail View And The Instruction List ........ 10-8 

10.2.3 Structure of the Variable Declaration Window................................................ 10-9 

10.3 Multiple Instances in the Variable Declaration ............................................. 10-10 

10.3.1 Using Multiple Instances............................................................................... 10-10 

10.3.2 Rules for Declaring Multiple Instances ......................................................... 10-11 

10.3.3 Entering a Multiple Instance in the Variable Declaration Window................ 10-11 

10.4 General Notes on Entering Statements and Comments .............................. 10-12 

10.4.1 Structure of the Code Section ...................................................................... 10-12 

10.4.2 Procedure for Entering Statements .............................................................. 10-13 

10.4.3 Entering Shared Symbols in a Program ....................................................... 10-14 

10.4.4 Title and Comments for Blocks and Networks ............................................. 10-15 

10.4.5 Entering Block Comments and Network Comments .................................... 10-16 

10.4.6 Working with Network Templates ................................................................. 10-17 

10.4.7 Search Function for Errors in the Code Section........................................... 10-18 

10.5 Editing LAD Elements in the Code Section .................................................. 10-19 

10.5.1 Settings for Ladder Logic Programming....................................................... 10-19 

10.5.2 Rules for Entering Ladder Logic Elements................................................... 10-19 

10.5.3 Illegal Logic Operations in Ladder ................................................................ 10-22 

10.6 Editing FBD Elements in the Code Section.................................................. 10-23 

10.6.1 Settings for Function Block Diagram Programming ..................................... 10-23 

10.6.2 Rules for Entering FBD Elements................................................................. 10-24 

10.7 Editing STL Statements in the Code Section ............................................... 10-26 

10.7.1 Settings for Statement List Programming..................................................... 10-26 

10.7.2 Rules for Entering STL Statements .............................................................. 10-26 

10.8 Updating Block Calls..................................................................................... 10-27 

10.8.1 Changing Interfaces...................................................................................... 10-28 

10.9 Saving Logic Blocks...................................................................................... 10-29 

11 Creating Data Blocks 11-1 

11.1 Basic Information on Creating Data Blocks.................................................... 11-1 

11.2 Declaration View of Data Blocks .................................................................... 11-2 

11.3 Data View of Data Blocks ............................................................................... 11-3 

11.4 Editing and Saving Data Blocks ..................................................................... 11-4 

11.4.1 Entering the Data Structure of Shared Data Blocks ....................................... 11-4 

11.4.2 Entering and Displaying the Data Structure 

of Data Blocks Referencing an FB (Instance DBs) ........................................ 11-5 

11.4.3 Entering the Data Structure of User-Defined Data Types (UDT) ................... 11-7 

11.4.4 Entering and Displaying the Structure of Data Blocks Referencing a UDT.... 11-8 

11.4.5 Editing Data Values in the Data View............................................................. 11-9 

11.4.6 Resetting Data Values to their Initial Values .................................................. 11-9 

11.4.7 Saving Data Blocks....................................................................................... 11-10 

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12 Parameter Assignment for Data Blocks 12-1 

12.1 Assigning Parameters to Technological Functions ........................................ 12-2 

13 Creating STL Source Files 13-1 

13.1 Basic Information on Programming in STL Source Files................................ 13-1 

13.2 Rules for Programming in STL Source Files .................................................. 13-2 

13.2.1 Rules for Entering Statements in STL Source Files ....................................... 13-2 

13.2.2 Rules for Declaring Variables in STL Source Files ........................................ 13-3 

13.2.3 Rules for Block Order in STL Source Files..................................................... 13-4 

13.2.4 Rules for Setting System Attributes in STL Source Files ............................... 13-4 

13.2.5 Rules for Setting Block Properties in STL Source Files ................................. 13-5 

13.2.6 Permitted Block Properties for Each Block Type............................................ 13-7 

13.3 Structure of Blocks in STL Source Files......................................................... 13-7 

13.3.1 Structure of Logic Blocks in STL Source Files ............................................... 13-8 

13.3.2 Structure of Data Blocks in STL Source Files ................................................ 13-9 

13.3.3 Structure of User-Defined Data Types in STL Source Files........................... 13-9 

13.4 Syntax and Formats for Blocks in STL Source Files .................................... 13-10 

13.4.1 Format Table of Organization Blocks ........................................................... 13-10 

13.4.2 Format Table of Function Blocks.................................................................. 13-11 

13.4.3 Format Table of Functions............................................................................ 13-12 

13.4.4 Format Table of Data Blocks ........................................................................ 13-13 

13.5 Creating STL Source Files ........................................................................... 13-14 

13.5.1 Creating STL Source Files ........................................................................... 13-14 

13.5.2 Editing S7 Source Files ................................................................................ 13-14 

13.5.3 Setting The Layout of Source Code Text ..................................................... 13-15 

13.5.4 Inserting Block Templates in STL Source Files............................................ 13-15 

13.5.5 Inserting the Contents of Other STL Source Files........................................ 13-15 

13.5.6 Inserting Source Code from Existing Blocks in STL Source Files................ 13-16 

13.5.7 Inserting External Source Files..................................................................... 13-16 

13.5.8 Generating STL Source Files from Blocks ................................................... 13-17 

13.5.9 Importing Source Files.................................................................................. 13-17 

13.5.10 Exporting Source Files.................................................................................. 13-18 

13.6 Saving and Compiling STL Source Files and Executing 

a Consistency Check.................................................................................... 13-19 

13.6.1 Saving STL Source Files .............................................................................. 13-19 

13.6.2 Checking Consistency in STL Source Files.................................................. 13-19 

13.6.3 Debugging STL Source Files........................................................................ 13-19 

13.6.4 Compiling STL Source Files ......................................................................... 13-20 

13.7 Examples of STL Source Files ..................................................................... 13-21 

13.7.1 Examples of Declaring Variables in STL Source Files ................................. 13-21 

13.7.2 Example of Organization Blocks in STL Source Files .................................. 13-22 

13.7.3 Example of Functions in STL Source Files................................................... 13-23 

13.7.4 Example of Function Blocks in STL Source Files......................................... 13-25 

13.7.5 Example of Data Blocks in STL Source Files............................................... 13-27 

13.7.6 Example of User-Defined Data Types in STL Source Files ......................... 13-28 

14 Displaying Reference Data 14-1 

14.1 Overview of the Available Reference Data..................................................... 14-1 

14.1.1 Cross-Reference List...................................................................................... 14-2 

14.1.2 Program Structure .......................................................................................... 14-4 

14.1.3 Assignment List .............................................................................................. 14-6 

14.1.4 Unused Symbols............................................................................................. 14-8 

14.1.5 Addresses Without Symbols........................................................................... 14-9 

14.1.6 Displaying Block Information for LAD, FBD, and STL .................................... 14-9 


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14.2 Working with Reference Data....................................................................... 14-10 

14.2.1 Ways of Displaying Reference Data............................................................. 14-10 

14.2.2 Displaying Lists in Additional Working Windows .......................................... 14-10 

14.2.3 Generating and Displaying Reference Data................................................. 14-11 

14.2.4 Finding Address Locations in the Program Quickly...................................... 14-12 

14.2.5 Example of Working with Address Locations ............................................... 14-13 

15 Checking Block Consistency and Time Stamps as a Block Property 15-1 

15.1 Checking Block Consistency .......................................................................... 15-1 

15.2 Time Stamps as a Block Property and Time Stamp Conflicts........................ 15-3 

15.3 Time Stamps in Logic Blocks ......................................................................... 15-4 

15.4 Time Stamps in Shared Data Blocks.............................................................. 15-5 

15.5 Time Stamps in Instance Data Blocks............................................................ 15-5 

15.6 Time Stamps in UDTs and Data Blocks Derived from UDTs ......................... 15-6 

15.7 Correcting the Interfaces in a Function, Function Block, or UDT ................... 15-6 

15.8 Avoiding Errors when Calling Blocks.............................................................. 15-7 

16 Configuring Messages 16-1 

16.1 The Message Concept.................................................................................... 16-1 

16.1.1 What Are the Different Messaging Methods?................................................. 16-1 

16.1.2 Choosing a Messaging Method ...................................................................... 16-3 

16.1.3 SIMATIC Components.................................................................................... 16-5 

16.1.4 Parts of a Message......................................................................................... 16-5 

16.1.5 Which Message Blocks Are Available? .......................................................... 16-6 

16.1.6 Formal Parameters, System Attributes, and Message Blocks ....................... 16-8 

16.1.7 Message Type and Messages........................................................................ 16-9 

16.1.8 How to Generate an STL Source File from Message-Type Blocks.............. 16-10 

16.1.9 Assigning Message Numbers....................................................................... 16-10 

16.1.10 Differences Between Project-Oriented and CPU-Oriented Assignment of 

Message Numbers........................................................................................ 16-11 

16.1.11 Options for Modifying the Message Number Assignment of a Project......... 16-11 

16.2 Project-Oriented Message Configuration ..................................................... 16-12 

16.2.1 How to Assign Project-Oriented Message Numbers .................................... 16-12 

16.2.2 Assigning and Editing Block-Related Messages .......................................... 16-12 

16.2.2.1 How to Create Block-Related Messages (Project-Oriented)........................ 16-13 

16.2.2.2 How to Edit Block-Related Messages (Project-Oriented)............................. 16-16 

16.2.2.3 How to Configure PCS 7 Messages (Project-Oriented) ............................... 16-16 

16.2.3 Assigning and Editing Symbol-Related Messages....................................... 16-18 

16.2.3.1 How to Assign and Edit Symbol-Related Messages (Project-Oriented) ...... 16-18 

16.2.4 Creating and Editing User-Defined Diagnostic Messages ........................... 16-19 

16.3 CPU-Oriented Message Configuration......................................................... 16-20 

16.3.1 How to Assign CPU-Oriented Message Numbers........................................ 16-20 

16.3.2 Assigning and Editing Block-Related Messages .......................................... 16-21 

16.3.2.1 How to Create Block-Related Messages (CPU-Oriented)............................ 16-21 

16.3.2.2 How to Edit Block-Related Messages (CPU-Oriented) ................................ 16-24 

16.3.2.3 How to Configure PCS 7 Messages (CPU-Oriented)................................... 16-25 

16.3.3 Assigning and Editing Symbol-Related Messages....................................... 16-26 

16.3.3.1 How to Assign and Edit Symbol-Related Messages (CPU-Oriented) .......... 16-26 

16.3.4 Assigning and Editing User-Specific Diagnostic Messages ......................... 16-27 

16.4 Tips for Editing Messages ............................................................................ 16-28 

16.4.1 Adding Associated Values to Messages ...................................................... 16-28 

16.4.2 Integrating Texts from Text Libraries into Messages ................................... 16-30 

16.4.3 Deleting Associated Values.......................................................................... 16-31 

16.5 Translating and Editing Operator Related Texts .......................................... 16-32 

16.5.1 Translating and Editing User Texts .............................................................. 16-32 

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16.6 Translating and Editing Text Libraries .......................................................... 16-34 

16.6.1 User Text Libraries ....................................................................................... 16-34 

16.6.2 Creating User Text Libraries......................................................................... 16-34 

16.6.3 How to Edit User Text Libraries.................................................................... 16-35 

16.6.4 System Text Libraries................................................................................... 16-36 

16.6.5 Translating Text Libraries ............................................................................. 16-36 

16.7 Transferring Message Configuration Data to the Programmable Controller 16-38 

16.8 Displaying CPU Messages and User-Defined Diagnostic Messages .......... 16-39 

16.8.1 Configuring CPU Messages ......................................................................... 16-42 

16.8.2 Displaying Stored CPU Messages ............................................................... 16-42 

16.9 Configuring the 'Reporting of System Errors' ............................................... 16-43 

16.9.1 Supported Components and Functional Scope............................................ 16-45 

16.9.2 Settings for "Report System Error" ............................................................... 16-48 

16.9.3 Generating Blocks for Reporting System Errors .......................................... 16-49 

16.9.4 Generated FB, DB ........................................................................................ 16-49 

16.9.5 Creating Foreign-Language Message Texts in 'Report System Error'......... 16-51 

17 Controlling and Monitoring Variables 17-1 

17.1 Configuring Variables for Operator Control and Monitoring ........................... 17-1 

17.2 Configuring Operator Control and Monitoring Attributes 

with Statement List, Ladder Logic, and Function Block Diagram................... 17-3 

17.3 Configuring Operator Control and Monitoring Attributes 

via the Symbol Table ...................................................................................... 17-4 

17.4 Changing Operator Control and Monitoring Attributes with CFC ................... 17-5 

17.5 Transferring Configuration Data to the 

Operator Interface Programmable Controller ................................................. 17-6 

18 Establishing an Online Connection and Making CPU Settings 18-1 

18.1 Establishing Online Connections.................................................................... 18-1 

18.1.1 Establishing an Online Connection via the "Accessible Nodes" Window....... 18-2 

18.1.2 Establishing an Online Connection via the Online Window of the Project ..... 18-3 

18.1.3 Online Access to PLCs in a Multiproject......................................................... 18-4 

18.1.4 Password Protection for Access to Programmable Controllers...................... 18-6 

18.1.5 Updating the Window Contents ...................................................................... 18-7 

18.2 Displaying and Changing the Operating Mode............................................... 18-8 

18.2.1 Displaying and Changing the Operating Mode............................................... 18-8 

18.3 Displaying and Setting the Time and Date ..................................................... 18-9 

18.3.1 CPU Clocks with Time Zone Setting and Summer/Winter Time .................... 18-9 

18.4 Updating the Firmware ................................................................................. 18-10 

18.4.1 Updating Firmware in Modules and Submodules Online ............................. 18-10 

19 Downloading and Uploading 19-1 

19.1 Downloading from the PG/PC to the Programmable Controller..................... 19-1 

19.1.1 Requirements for Downloading ...................................................................... 19-1 

19.1.2 Differences Between Saving and Downloading Blocks.................................. 19-2 

19.1.3 Load Memory and Work Memory in the CPU................................................. 19-3 

19.1.4 Download Methods Dependent on the Load Memory .................................... 19-4 

19.1.5 Downloading a Program to the S7 CPU......................................................... 19-5 

19.1.5.1 Downloading with Project Management ......................................................... 19-5 

19.1.5.2 Downloading without Project Management .................................................... 19-6 

19.1.5.3 Reloading Blocks in the Programmable Controller......................................... 19-6 

19.1.5.4 Saving Downloaded Blocks on Integrated EPROM ....................................... 19-7 

19.1.5.5 Downloading via EPROM Memory Cards ...................................................... 19-7 

19.2 Compiling and Downloading Several Objects from the PG............................ 19-9 

19.2.1 Requirements for and Notes on Downloading................................................ 19-9 

19.2.2 Compiling and Downloading Objects............................................................ 19-11 


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19.3 Uploading from the Programmable Controller to the PG/PC........................ 19-13 

19.3.1 Uploading a Station ...................................................................................... 19-14 

19.3.2 Uploading Blocks from an S7 CPU............................................................... 19-15 

19.3.3 Editing Uploaded Blocks in the PG/PC......................................................... 19-16 

19.3.3.1 Editing Uploaded Blocks if the User Program is on the PG/PC ................... 19-17 

19.3.3.2 Editing Uploaded Blocks if the User Program is Not on the PG/PC............. 19-17 

19.4 Deleting on the Programmable Controller .................................................... 19-18 

19.4.1 Erasing the Load/Work Memory and Resetting the CPU ............................. 19-18 

19.4.2 Deleting S7 Blocks on the Programmable Controller ................................... 19-19 

19.5 Compressing the User Memory (RAM) ........................................................ 19-20 

19.5.1 Gaps in the User Memory (RAM) ................................................................. 19-20 

19.5.2 Compressing the Memory Contents of an S7 CPU...................................... 19-21 

20 Testing with the Variable Table 20-1 

20.1 Introduction to Testing with Variable Tables .................................................. 20-1 

20.2 Basic Procedure when Monitoring and Modifying with the Variable Table .... 20-2 

20.3 Editing and Saving Variable Tables................................................................ 20-3 

20.3.1 Creating and Opening a Variable Table ......................................................... 20-3 

20.3.2 Copying/Moving Variable Tables.................................................................... 20-3 

20.3.3 Saving a Variable Table.................................................................................. 20-4 

20.4 Entering Variables in Variable Table .............................................................. 20-4 

20.4.1 Inserting Addresses or Symbols in a Variable Table...................................... 20-4 

20.4.2 Inserting a Contiguous Address Range in a Variable Table........................... 20-6 

20.4.3 Inserting Modify Values .................................................................................. 20-7 

20.4.4 Upper Limits for Entering Timers.................................................................... 20-7 

20.4.5 Upper Limits for Entering Counters ................................................................ 20-8 

20.4.6 Inserting Comment Lines................................................................................ 20-9 

20.4.7 Examples ........................................................................................................ 20-9 

20.5 Establishing a Connection to the CPU ......................................................... 20-13 

20.6 Monitoring Variables..................................................................................... 20-14 

20.6.1 Introduction to Monitoring Variables ............................................................. 20-14 

20.6.2 Defining the Trigger for Monitoring Variables............................................... 20-14 

20.7 Modifying Variables ...................................................................................... 20-16 

20.7.1 Introduction to Modifying Variables .............................................................. 20-16 

20.7.2 Defining the Trigger for Modifying Variables ................................................ 20-17 

20.8 Forcing Variables.......................................................................................... 20-19 

20.8.1 Safety Measures When Forcing Variables ................................................... 20-19 

20.8.2 Introduction to Forcing Variables.................................................................. 20-20 

20.8.3 Differences Between Forcing and Modifying Variables................................ 20-22 

21 Testing Using Program Status 21-1 

21.1 Program Status Display.................................................................................. 21-2 

21.2 What You Should Know About Testing in Single-Step Mode/Breakpoints..... 21-3 

21.3 What You Should Know About the HOLD Mode ............................................ 21-5 

21.4 Program Status of Data Blocks ...................................................................... 21-6 

21.5 Setting the Display for Program Status .......................................................... 21-7 

21.6 Setting the Mode for the Test ......................................................................... 21-8 

22 Testing using the Simulation Program (Optional Package) 22-1 

22.1 Testing using the Simulation Program S7-PLCSIM (Optional Package) ....... 22-1 

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23 Diagnostics 23-1 

23.1 Hardware Diagnostics and Troubleshooting................................................... 23-1 

23.2 Diagnostics Symbols in the Online View ........................................................ 23-3 

23.3 Diagnosing Hardware: Quick View ................................................................. 23-5 

23.3.1 Calling the Quick View.................................................................................... 23-5 

23.3.2 Information Functions in the Quick View ........................................................ 23-5 

23.4 Diagnosing Hardware: Diagnostic View ......................................................... 23-6 

23.4.1 Calling the Diagnostic View ............................................................................ 23-6 

23.4.2 Information Functions in the Diagnostic View................................................. 23-8 

23.5 Module Information ......................................................................................... 23-9 

23.5.1 Options for Displaying the Module Information .............................................. 23-9 

23.5.2 Module Information Functions ...................................................................... 23-10 

23.5.3 Scope of the Module Type-Dependent Information...................................... 23-12 

23.5.4 Displaying the Module Status of PA Field Devices and 

DP Slaves After a Y-Link .............................................................................. 23-13 

23.6 Diagnosing in STOP Mode ........................................................................... 23-15 

23.6.1 Basic Procedure for Determining the Cause of a STOP .............................. 23-15 

23.6.2 Stack Contents in STOP Mode..................................................................... 23-15 

23.7 Checking Scan Cycle Times to Avoid Time Errors....................................... 23-17 

23.8 Flow of Diagnostic Information ..................................................................... 23-18 

23.8.1 System Status List SSL ................................................................................ 23-19 

23.8.2 Sending Your Own Diagnostic Messages .................................................... 23-22 

23.8.3 Diagnostic Functions .................................................................................... 23-23 

23.9 Program Measures for Handling Errors........................................................ 23-24 

23.9.1 Evaluating the Output Parameter RET_VAL ................................................ 23-25 

23.9.2 Error OBs as a Reaction to Detected Errors ................................................ 23-26 

23.9.3 Inserting Substitute Values for Error Detection ............................................ 23-31 

23.9.4 I/O Redundancy Error (OB70) ...................................................................... 23-33 

23.9.5 CPU Redundancy Error (OB72) ................................................................... 23-34 

23.9.6 Time Error (OB80) ........................................................................................ 23-35 

23.9.7 Power Supply Error (OB81).......................................................................... 23-36 

23.9.8 Diagnostic Interrupt (OB82).......................................................................... 23-37 

23.9.9 Insert/Remove Module Interrupt (OB83) ...................................................... 23-38 

23.9.10 CPU Hardware Fault (OB84)........................................................................ 23-39 

23.9.11 Program Sequence Error (OB85) ................................................................. 23-40 

23.9.12 Rack Failure (OB86)..................................................................................... 23-41 

23.9.13 Communication Error (OB87) ....................................................................... 23-42 

23.9.14 Programming Error (OB121) ........................................................................ 23-43 

23.9.15 I/O Access Error (OB122)............................................................................. 23-44 

24 Printing and Archiving 24-1 

24.1 Printing Project Documentation ...................................................................... 24-1 

24.1.1 Basic Procedure when Printing ...................................................................... 24-2 

24.1.2 Print Functions................................................................................................ 24-2 

24.1.3 Special Note on Printing the Object Tree ....................................................... 24-3 

24.2 Archiving Projects and Libraries ..................................................................... 24-4 

24.2.1 Uses for Saving/Archiving............................................................................... 24-5 

24.2.2 Requirements for Archiving ............................................................................ 24-5 

24.2.3 Procedure for Archiving/Retrieving................................................................. 24-6 

25 Working with M7 Programmable Control Systems 25-1 

25.1 Procedure for M7 Systems ............................................................................. 25-1 

25.2 Optional Software for M7 Programming ......................................................... 25-3 

25.3 M7-300/M7-400 Operating Systems............................................................... 25-6 


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Contents 

26 Tips and Tricks 26-1 

26.1 Exchanging Modules in the Configuration Table............................................ 26-1 

26.2 Projects with a Large Number of Networked Stations.................................... 26-1 

26.3 Rearranging .................................................................................................... 26-2 

26.4 Editing Symbols Across Multiple Networks .................................................... 26-2 

26.5 Testing with the Variable Table ...................................................................... 26-3 

26.6 Modifying Variables With the Program Editor................................................. 26-4 

26.7 Virtual Work Memory ...................................................................................... 26-5 

A Appendix A-1 

A.1 Operating Modes ..............................................................................................A-1 

A.1.1 Operating Modes and Mode Transitions ..........................................................A-1 

A.1.2 STOP Mode ......................................................................................................A-4 

A.1.3 STARTUP Mode ...............................................................................................A-5 

A.1.4 RUN Mode ......................................................................................................A-13 

A.1.5 HOLD Mode....................................................................................................A-14 

A.2 Memory Areas of S7 CPUs.............................................................................A-15 

A.2.1 Distribution of the Memory Areas ...................................................................A-15 

A.2.2 Load Memory and Work Memory ...................................................................A-16 

A.2.3 System Memory..............................................................................................A-18 

A.2.3.1 Using the System Memory Areas ...................................................................A-18 

A.2.3.2 Process-Image Input/Output Tables...............................................................A-20 

A.2.3.3 Local Data Stack.............................................................................................A-24 

A.2.3.4 Interrupt Stack ................................................................................................A-25 

A.2.3.5 Block Stack .....................................................................................................A-26 

A.2.3.6 Diagnostic Buffer ............................................................................................A-27 

A.2.3.7 Evaluating the Diagnostic Buffer ....................................................................A-27 

A.2.3.8 Retentive Memory Areas on S7-300 CPUs....................................................A-29 

A.2.3.9 Retentive Memory Areas on S7-400 CPUs....................................................A-30 

A.2.3.10 Configurable Memory Objects in the Work Memory.......................................A-31 

A.3 Data Types and Parameter Types..................................................................A-32 

A.3.1 Introduction to Data Types and Parameter Types..........................................A-32 

A.3.2 Elementary Data Types ..................................................................................A-33 

A.3.2.1 Format of the Data Type INT (16-Bit Integers)...............................................A-34 

A.3.2.2 Format of the Data Type DINT (32-Bit Integers) ............................................A-34 

A.3.2.3 Format of the Data Type REAL (Floating-Point Numbers).............................A-35 

A.3.2.4 Format of the Data Types WORD and DWORD in 

Binary Coded Decimal Numbers ....................................................................A-39 

A.3.2.5 Format of the Data Type S5TIME (Time Duration) ........................................A-40 

A.3.3 Complex Data Types ......................................................................................A-41 

A.3.3.1 Format of the Data Type DATE_AND_TIME..................................................A-42 

A.3.3.2 Using Complex Data Types............................................................................A-44 

A.3.3.3 Using Arrays to Access Data..........................................................................A-45 

A.3.3.4 Using Structures to Access Data....................................................................A-48 

A.3.3.5 Using User-Defined Data Types to Access Data ...........................................A-50 

A.3.4 Parameter Types ............................................................................................A-52 

A.3.4.1 Format of the Parameter Types BLOCK, COUNTER, TIMER .......................A-53 

A.3.4.2 Format of the Parameter Type POINTER ......................................................A-53 

A.3.4.3 Using the Parameter Type POINTER.............................................................A-54 

A.3.4.4 Block for Changing the Pointer.......................................................................A-55 

A.3.4.5 Format of the Parameter Type ANY ...............................................................A-58 

A.3.4.6 Using the Parameter Type ANY .....................................................................A-61 

A.3.4.7 Assigning Data Types to Local Data of Logic Blocks .....................................A-64 

A.3.4.8 Permitted Data Types when Transferring Parameters ...................................A-66 

A.3.4.9 Transferring to IN_OUT Parameters of a Function Block...............................A-71 

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Index 

A.4 Working with Older Projects ...........................................................................A-72 

A.4.1 Converting Version 1 Projects ........................................................................A-72 

A.4.2 Converting Version 2 Projects ........................................................................A-73 

A.4.3 Notes on STEP 7 V.2.1 Projects with GD Communication ............................A-74 

A.4.4 DP-Slaves with Missing or Faulty GSD Files..................................................A-74 

A.5 Sample Programs ...........................................................................................A-75 

A.5.1 Sample Projects and Sample Programs.........................................................A-75 

A.5.2 Sample Program for an Industrial Blending Process......................................A-77 

A.5.2.1 Defining Logic Blocks .....................................................................................A-79 

A.5.2.2 Assigning Symbolic Names ............................................................................A-81 

A.5.2.3 Creating the FB for the Motor .........................................................................A-83 

A.5.2.4 Creating the FC for the Valves .......................................................................A-88 

A.5.2.5 Creating OB1 ..................................................................................................A-90 

A.5.3 Example of Handling Time-of-Day Interrupts .................................................A-96 

A.5.3.1 Structure of the User Program "Time-of-Day Interrupts"................................A-96 

A.5.3.2 FC12 ...............................................................................................................A-98 

A.5.3.3 OB10.............................................................................................................A-100 

A.5.3.4 OB1 and OB80 .............................................................................................A-102 

A.5.4 Example of Handling Time-Delay Interrupts.................................................A-104 

A.5.4.1 Structure of the User Program "Time-Delay Interrupts" ...............................A-104 

A.5.4.2 OB20.............................................................................................................A-106 

A.5.4.3 OB1...............................................................................................................A-108 

A.5.4.4 Example of Masking and Unmasking Synchronous Errors ..........................A-110 

A.5.4.5 Example of Disabling and Enabling Interrupts and 

Asynchronous Errors (SFC39 and SFC40) ..................................................A-115 

A.5.4.6 Example of the Delayed Processing of Interrupts and 

Asynchronous Errors (SFC41 and SFC42) ..................................................A-116 

A.6 Accessing Process and I/O Data Areas .......................................................A-117 

A.6.1 Accessing the Process Data Area ................................................................A-117 

A.6.2 Accessing the Peripheral Data Area.............................................................A-118 

A.7 Setting the Operating Behavior ....................................................................A-120 

A.7.1 Changing the Behavior and Properties of Modules......................................A-121 

A.7.2 Updating the Firmware (of the Operating System) in 

Modules and Submodules Offline.................................................................A-124 

A.7.3 Using the Clock Functions............................................................................A-126 

A.7.4 Using Clock Memory and Timers .................................................................A-128 

Index-1 


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1 Introducing the Product and Installing the 

Software 

1.1 Overview of STEP 7 

What is STEP 7? 

STEP 7 is the standard software package used for configuring and programming 

SIMATIC programmable logic controllers. It is part of the SIMATIC industry 

software. There are the following versions of the STEP 7 Standard package: 

• STEP 7 Micro/DOS and STEP 7 Micro/Win for simpler stand-alone applications 

on the SIMATIC S7-200. 

• STEP 7 for applications on SIMATIC S7-300/S7-400, SIMATIC M7-300/M7-400, 

and SIMATIC C7 with a wider range of functions: 

- Can be extended as an option by the software products in the SIMATIC 

Industry Software (see also Extended Uses of the STEP 7 Standard 

Package) 

- Opportunity of assigning parameters to function modules and 

communications processors 

- Forcing and multicomputing mode 

- Global data communication 

- Event-driven data transfer using communication function blocks 

- Configuring connections 

STEP 7 is the subject of this documentation, STEP 7 Micro is described in the 

"STEP 7 Micro/DOS" documentation. 

Basic Tasks 

When you create an automation solution with STEP 7, there are a series of basic 

tasks. The following figure shows the tasks that need to be performed for most 

projects and assigns them to a basic procedure. It refers you to the relevant 

chapter thus giving you the opportunity of moving through the manual to find taskrelated 

information. 


A5E00706944-01 1-1

Introducing the Product and Installing the Software 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


1-2 A5E00706944-01


Alternative Procedures 

As shown in the figure above, you have two alternative procedures: 

• You can configure the hardware first and then program the blocks. 

• You can, however, program the blocks first without configuring the hardware. 

This is recommended for service and maintenance work, for example, to 

integrate programmed blocks into in an existing project. 

Brief Description of the Individual Steps 

• Install STEP 7 and license keys 

The first time you use STEP 7, install it and transfer the license keys from 

diskette to the hard disk (see also Installing STEP 7 and Authorization). 

• Plan your controller 

Before you work with STEP 7, plan your automation solution from dividing the 

process into individual tasks to creating a configuration diagram (see also Basic 

Procedure for Planning an Automation Project). 

• Design the program structure 

Turn the tasks described in the draft of your controller design into a program 

structure using the blocks available in STEP 7 (see also Blocks in the User 

Program). 

• Start STEP 7 

You start STEP 7 from the Windows user interface (see also Starting STEP 7). 

• Create a project structure 

A project is like a folder in which all data are stored in a hierarchical structure 

and are available to you at any time. After you have created a project, all other 

tasks are executed in this project (see also Project Structure). 

• Configure a station 

When you configure the station you specify the programmable controller you 

want to use; for example, SIMATIC 300, SIMATIC 400, SIMATIC S5 (see also 

Inserting Stations). 

• Configure hardware 

When you configure the hardware you specify in a configuration table which 

modules you want to use for your automation solution and which addresses are 

to be used to access the modules from the user program. The properties of the 

modules can also be assigned using parameters (see also Basic Procedure for 

Configuring Hardware) . 

• Configure networks and communication connections 

The basis for communication is a pre-configured network. For this, you will need 

to create the subnets required for your automation networks, set the subnet 

properties, and set the network connection properties and any communication 

connections required for the networked stations (see also Procedure for 

Configuring a Subnet). 

• Define symbols 

You can define local or shared symbols, which have more descriptive names, in 

a symbol table to use instead of absolute addresses in your user program (see 

also Creating a Symbol Table). 


A5E00706944-01 1-3


• Create the program 

Using one of the available programming languages create a program linked to a 

module or independent of a module and store it as blocks, source files, or 

charts (see also Basic Procedure for Creating Logic Blocks and Basic 

Information on Programming in STL Source Files). 

• S7 only: generate and evaluate reference data 

You can make use of these reference data to make debugging and modifying 

your user program easier (see also Overview of the Available Reference Data). 

• Configure messages 

You create block-related messages, for example, with their texts and attributes. 

Using the transfer program you transfer the message configuration data created 

to the operator interface system database (for example, SIMATIC WinCC, 

SIMATIC ProTool), see also Configuring Messages. 

• Configure operator control and monitoring variables 

You create operator control and monitoring variables once in STEP 7 and 

assign them the required attributes. Using the transfer program you transfer the 

operator control and monitoring variables created to the database of the 

operator interface system WinCC (see also Configuring Variables for Operator 

Control and Monitoring). 

• Download programs to the programmable controller 

S7 only: after all configuration, parameter assignment, and programming tasks 

are completed, you can download your entire user program or individual blocks 

from it to the programmable controller (programmable module for your hardware 

solution). (See also Requirements for Downloading.) The CPU already contains 

the operating system. 

M7 only: choose a suitable operating system for your automation solution from 

a number of different operating systems and transfer this on its own or together 

with the user program to the required data medium of the M7 programmable 

control system. 

• Test programs 

S7 only: for testing you can either display the values of variables from your user 

program or a CPU, assign values to the variables, and create a variable table 

for the variables that you want to display or modify (see also Introduction to 

Testing with the Variable Table). 

M7 only: test the user program with a high-level language-debugging tool. 

• Monitor operation, diagnose hardware 

You determine the cause of a module fault by displaying online information 

about a module. You determine the causes for errors in user program 

processing with the help of the diagnostic buffer and the stack contents. You 

can also check whether a user program can run on a particular CPU (see also 

Hardware Diagnostics and Displaying Module Information). 

• Document the plant 

After you have created a project/plant, it makes sense to produce clear 

documentation of the project data to make further editing of the project and any 

service activities easier (see also Printing Project Documentation). DOCPRO, 

the optional tool for creating and managing plant documentation, allows you to 

structure the project data, put it into wiring manual form, and print it out in a 

common format. 


1-4 A5E00706944-01


Specialized Topics 

When you create an automation solution there are a number of special topics that 

may be of interest to you: 

• Multicomputing - Synchronous Operation of Several CPUs (see also 

Multicomputing - Synchronous Operation of Several CPUs) 

• More than One User Working in a Project (see also More than One User Editing 

Projects) 

• Working with M7 Systems (see also Procedure for M7 Systems) 


A5E00706944-01 1-5


1.2 The STEP 7 Standard Package 

Standards Used 

The SIMATIC programming languages integrated in STEP 7 are compliant with 

EN 61131-3. The standard package matches the graphic and object oriented 

operating philosophy of Windows and runs under the operating system 

MS Windows 2000 Professional (as of now referred to as Windows 2000) as well 

as MS Windows XP Professional (as of now referred to as Windows XP) and 

MS Windows Server 2003. 

Functions of the standard package 

The standard software supports you in all phases of the creation process of an 

automation task, such as: 

• Setting up and managing projects 

• Configuring and assigning parameters to hardware and communications 

• Managing symbols 

• Creating programs, for example, for S7 programmable controllers 

• Downloading programs to programmable controllers 

• Testing the automation system 

• Diagnosing plant failures 

The STEP 7 software user interface has been designed to meet the latest 

state-of-the-art ergonomics and makes it easy for you to get started. 

The documentation for the STEP 7 software product provides all the information 

online in the online Help and in electronic manuals in PDF format. 


1-6 A5E00706944-01


Applications in STEP 7 

The STEP 7 Standard package provides a series of applications (tools) within the 

software: 

 

 

 

 

 

 

 

 

 

 

 

 

You do not need to open the tools separately; they are started automatically when 

you select the corresponding function or open an object. 


A5E00706944-01 1-7


SIMATIC Manager 

The SIMATIC Manager manages all the data that belong to an automation project 

− regardless of which programmable control system (S7/M7/C7) they are designed 

for. The tools needed to edit the selected data are started automatically by the 

SIMATIC Manager. 

Symbol Editor 

With the Symbol Editor you manage all the shared symbols. The following 

functions are available: 

• Setting symbolic names and comments for the process signals (inputs/outputs), 

bit memory, and blocks 

• Sort functions 

• Import/export to/from other Windows programs 

The symbol table created with this tool is available to all the other tools. Any 

changes to the properties of a symbol are therefore recognized automatically by all 

tools. 


1-8 A5E00706944-01


Diagnosing Hardware 

These functions provide you with an overview of the status of the programmable 

controller. An overview can display symbols to show whether every module has a 

fault or not. A double-click on the faulty module displays detailed information about 

the fault. The scope of this information depends on the individual module: 

• Display general information about the module (for example, order number, 

version, name) and the status of the module (for example, faulty) 

• Display the module faults (for example, channel fault) for the central I/O and DP 

slaves 

• Display messages from the diagnostic buffer 

For CPUs the following additional information is displayed: 

• Causes of faults in the processing of a user program 

• Display the cycle duration (of the longest, shortest, and last cycle) 

• MPI communication possibilities and load 

• Display performance data (number of possible inputs/outputs, bit memory, 

counters, timers, and blocks) 

Programming Languages 

The programming languages Ladder Logic, Statement List, and Function Block 

Diagram for S7-300 and S7-400 are an integral part of the standard package. 

• Ladder Logic (or LAD) is a graphic representation of the STEP 7 programming 

language. Its syntax for the instructions is similar to a relay ladder logic 

diagram: Ladder allows you to track the power flow between power rails as it 

passes through various contacts, complex elements, and output coils. 

• Statement List (or STL) is a textual representation of the STEP 7 programming 

language, similar to machine code. If a program is written in Statement List, the 

individual instructions correspond to the steps with which the CPU executes the 

program. To make programming easier, Statement List has been extended to 

include some high-level language constructions (such as structured data access 

and block parameters). 

• Function Block Diagram (FBD) is a graphic representation of the STEP 7 

programming language and uses the logic boxes familiar from Boolean algebra 

to represent the logic. Complex functions (for example, math functions) can be 

represented directly in conjunction with the logic boxes. 

Other programming languages are available as optional packages. 


A5E00706944-01 1-9


Hardware Configuration 

You use this tool to configure and assign parameters to the hardware of an 

automation project. The following functions are available: 

• To configure the programmable controller you select racks from an electronic 

catalog and arrange the selected modules in the required slots in the racks. 

• Configuring the distributed I/O is identical to the configuration of the central I/O. 

Channel-granular I/O is also supported. 

• In the course of assigning parameters to the CPU you can set properties such 

as startup behavior and scan cycle time monitoring guided by menus. 

Multicomputing is supported. The data entered are stored in system data 

blocks. 

• In the course of assigning parameters to the modules, all the parameters you 

can set are set using dialog boxes. There are no settings to be made using DIP 

switches. The assignment of parameters to the modules is done automatically 

during startup of the CPU. This means, for example, that a module can be 

exchanged without assigning new parameters. 

• Assigning parameters to function modules (FMs) and communications 

processors (CPs) is also done within the Hardware Configuration tool in exactly 

the same way as for the other modules. Module-specific dialog boxes and rules 

exist for every FM and CP (included in the scope of the FM/CP function 

package). The system prevents incorrect entries by only offering valid options in 

the dialog boxes. 

NetPro (Network Configuration) 

Using NetPro time-driven cyclic data transfer via the MPI is possible where you: 

• Select the communication nodes 

• Enter the data source and data target in a table; all blocks (SDBs) to be 

downloaded are generated automatically and completely downloaded to all 

CPUs automatically 

Event-driven data transfer is also possible where you: 

• Set the communication connections 

• Select the communication or function blocks from the integrated block library 

• Assign parameters to the selected communication or function blocks in your 

chosen programming language 


1-10 A5E00706944-01


1.3 What's New in STEP 7, Version 5.4? 

The following subject areas have been updated: 

• SIMATIC Manager 

• Configuring and Diagnosing Hardware 

• Configuring Networks and Connections 

• Standard Libraries 

• Report System Error 


• As of STEP 7 V5.4, there are two formats available for displaying the date and 

the time. You can select a display in the respective STEP 7 national language 

and or in ISO 8601 standard format. To make this setting, go to the SIMATIC 

Manager, open the "Customize" dialog box and select the "Date and Time" tab. 

• As of STEP 7 V5.4, you can have module times displayed in the local time for 

your programming device (PG)/PC. To make this setting, go to the SIMATIC 

Manager, open the "Customize" dialog box and select the "Date and Time" tab. 

• As of STEP 7 V5.4, you have the option of restricting access to projects and 

libraries by assigning a passwords to them. In order to do this, you must have 

installed SIMATIC Logon V1.3 SP1 (as of now referred to as SIMATIC Logon) 

(see What You Should Know About Access). 

• As of STEP 7 V5.4, after setting up access protection for projects and libraries, 

you have the option of keeping a change log that records online actions such as 

"Download", "Operating Mode Changes", and "Reset". In order to do this, you 

must have installed SIMATIC Logon V1.3 SP1 (as of now referred to as 

SIMATIC Logon) (see What You Should Know About Access Protection). 


A5E00706944-01 1-11


Configuring and Diagnosing Hardware 

• The "Information and Maintenance" process is supported in order to be able to 

read identification data from or write identification data to modules. This function 

is also available in the SIMATIC Manager (see Identification and Maintenance 

(I&M)). 

• Identification data can also be written to PROFIBUS DP interface modules 

during redundant mode (by means of "Accessible Nodes"). The interface 

module must support this function. 

• CAx data can be imported and exported. In this way, data can be exchanged 

between STEP 7 and CAD systems or CAE engineering systems (see 

Exporting and Importing CAx Data) 

• The firmware for PROFIBUS DP interface modules can also be updated during 

redundant mode, as long as such a module will support this process. Each of 

the redundantly used interface modules can now send the updated firmware 

through the active backplane bus to the other, redundant interface module. 

• The "Software Redundancy" function now allows PA links with subordinate PA 

slaves to be copied and redundantly inserted (see Configuring SW 

Redundancy) 

• Applications for editing objects in HW Config can now be started with the Edit > 

Open Object menu command (see Opening Objects in HW Config). 

• You can configure a watchdog time for PROFINET IO devices (see Configuring 

the Watchdog Time) 

• As of STEP 7 V5.4, you can have module times displayed in the local time of 

your programming device (PG)/PC. 

Configuring Networks and Connections 

• PROFINET IO with IRT Communication (Isochronous Realtime) is supported. 

This means that short and equal-length bus-cycle times can also be configured 

for PROFINET IO (see Introduction: Isochronous Realtime Ethernet). 

• There is improved handling when inserting copied IO devices into another 

station. If the IP addresses are already assigned, you can specify the action to 

be taken upon insertion (retain addresses or assign new ones). 

• In a manner similar to that for PROFIBUS DP slaves, you can now set the 

watchdog time for PROFINET IO devices: as an object property of the IO device 

in the "IO Cycle" tab. 

• When using optical components for PROFIBUS DP: when configuring with an 

optical ring, you can specify the optical link modules (OLMs) to be used. This 

makes calculation of bus parameters more exact. In addition, it means that the 

bus cycle time can be shortened when higher-performance components are 

being used. 


1-12 A5E00706944-01


Standard Libraries 

• The standard library "Communication Blocks" has been expanded with the 

blocks FB 67 and FB 68 for open TCP/IP communication. 

• The standard library "Communication Blocks" has been expanded with the 

blocks FB 20, FB 21, FB 22 and FB 23 for cyclic accessing of user data in 

accordance with the German PROFIBUS User Organization [PROFIBUS 

Nutzerorganisation e.V. (PNO)]. 

• In addition to the existing redundance library "Redundant IO (V1)", as of 

STEP 7 V5.4 there is the new block library "Redundant IO CGP" (channel 

granular peripheral devices). It supports redundancy for single module 

channels. You can find further information in the context-sensitive block help or 

the STEP 7 readme file. A current list of supported modules is available under 

the FAQs here: http://support.automation.siemens.com/. 

Report System Error 

• As of STEP 7 V5.4, a data block (DB 125) for PROFIBUS is supported. This 

data block can be used to output diagnostic events on an HMI device. 


A5E00706944-01 1-13


1.4 Extended Uses of the STEP 7 Standard Package 

The standard package can be extended by optional software packages that are 

grouped into the following three software classes: 

• Engineering Tools; 

these are higher-level programming languages and technology-oriented 

software. 

• Run-Time Software; 

these contain off-the-shelf run-time software for the production process. 

• Human Machine Interfaces (HMI); 

this is software especially for operator control and monitoring. 

The following table shows the optional software you can use depending on your 

programmable control system: 

S7-300 

S7-400 

STEP 7 

M7-300 

M7-400 

Engineering Tools 

• Borland C/C++ o 

• CFC + 1) + + 2) 

• DOCPRO + + 3) + 

• HARDPRO + 

• M7 ProC/C++ o 

• S7 GRAPH + 1) + 2) 

• S7 HiGraph + + 

• S7 PDIAG + 

• S7 PLCSIM + + 

• S7 SCL + + 

• Teleservice + + + 

Run-Time Software 

• Fuzzy Control + + 

• M7-DDE Server + 

• M7-SYS RT o 

• Modular PID Control + + 

• PC-DDE Server + 

• PRODAVE MPI + 

• Standard PID Control + + 

Human Machine Interface 

• ProAgent 

• SIMATIC ProTool 

• SIMATIC ProTool/Lite o 

• SIMATIC WinCC 

o = obligatory 

+ = optional 

1) = recommended from S7-400 upwards 

2) = not recommended for C7-620 

3) = not for C programs 

C7-620 


1-14 A5E00706944-01


1.4.1 Engineering Tools 

Engineering Tools are task-oriented tools that can be used to extend the standard 

package. Engineering Tools include: 

• High-level languages for programmers 

• Graphic languages for technical staff 

• Supplementary software for diagnostics, simulation, remote maintenance, plant 

documentation etc. 

 

 

 

 

 

 

 

 

 

 

High-Level Languages 

The following languages are available as optional packages for use in 

programming the SIMATIC S7-300/S7-400 programmable logic controllers: 

• S7 GRAPH is a programming language used to program sequential controls 

(steps and transitions). In this language, the process sequence is divided into 

steps. The steps contain actions to control the outputs. The transition from one 

step to another is controlled by switching conditions. 

• S7 HiGraph is a programming language used to describe asynchronous, 

non-sequential processes in the form of state graphs. To do this, the plant is 

broken down into individual functional units which can each take on different 

states. The functional units can be synchronized by exchanging messages 

between the graphs. 

• S7 SCL is a high-level text-based language to EN 61131-3 (IEC 1131-3). It 

contains language constructs similar to those found in the programming 

languages C and Pascal. S7 SCL is therefore particularly suitable for users 

familiar with high-level language programming. S7 SCL can be used, for 

example, to program complex or frequently recurring functions. 


A5E00706944-01 1-15


Graphic Language 

CFC for S7 and M7 is a programming language for interconnecting functions 

graphically. These functions cover a wide range of simple logic operations through 

to complex controls and control circuits. A large number of such function blocks are 

available in the form of blocks in a library. You program by copying the blocks into 

a chart and interconnecting the blocks with connecting lines. 

Supplementary Software 

• Borland C++ (M7 only) contains the Borland development environment. 

• With DOCPRO you can organize all configuration data created under STEP 7 

into wiring manuals. These wiring manuals make it easy to manage the 

configuration data and allow the information to be prepared for printing 

according to specific standards. 

• HARDPRO is the hardware configuration system for S7-300 with user support 

for large-scale configuration of complex automation tasks. 

• M7 ProC/C++ (M7 only) allows integration of the Borland development 

environment for the programming languages C and C++ into the STEP 7 

development environment. 

• You can use S7 PLCSIM (S7 only) to simulate S7 programmable controllers 

connected to the programming device or PC for purposes of testing. 

• S7 PDIAG (S7 only) allows standardized configuration of process diagnostics 

for SIMATIC S7-300/S7-400. Process diagnostics let you detect faults and 

faulty states of PLC I/O (for example, limit switch not reached). 

• TeleService is a solution providing functions for online programming and 

servicing of remote S7 and M7 PLCs via the telecommunications network with 

your PG/PC. 


1-16 A5E00706944-01


1.4.2 Run-Time Software 

Runtime software provides ready-to-use solutions you can call in user program and 

is directly implemented in the automation solution. It includes: 

• Controllers for SIMATIC S7, for example, standard, modular and fuzzy logic 

control 

• Tools for linking the programmable controllers with Windows applications 

• A real-time operating system for SIMATIC M7 

 

 

 

 

 

 

 

 

Controllers for SIMATIC S7 

• Standard PID Control allows you to integrate closed-loop controllers, pulse 

controllers, and step controllers into the user program. The parameter 

assignment tool with integrated controller setting allows you to set the controller 

up for optimum use in a very short time. 

• Modular PID Control comes into play if a simple PID controller is not sufficient to 

solve your automation task. You can interconnect the included standard 

function blocks to create almost any controller structure. 

• With Fuzzy Control you can create fuzzy logic systems. These systems are 

used if the mathematical definition of processes is impossible or highly complex, 

if processes and sequencers do not react as expected, if linearity errors occur 

and if, on the other hand, information on the process is available. 


A5E00706944-01 1-17


Tools for Linking with Windows 

• PRODAVE MPI is a toolbox for process data traffic between SIMATIC S7, 

SIMATIC M7, and SIMATIC C7. It automatically controls the data flow across 

the MPI interface. 

• An M7 DDE server (Dynamic Data Exchange) can be used to link Windows 

applications to process variables in SIMATIC M7, without additional 

programming effort. 

Real-Time Operating System 

• M7-SYS RT contains the operating system M7 RMOS 32 and system programs. 

It is a prerequisite for the use of the M7-ProC/C++ and CFC for SIMATIC M7 

packages. 


1-18 A5E00706944-01


1.4.3 Human Machine Interface 

Human Machine Interface (HMI) is a software especially designed for operator 

control and monitoring in SIMATIC. 

• The open process visualization system SIMATIC WinCC is a standard operator 

interface with all the important operator control and monitoring functions which 

can be used in any branch of industry and with any technology. 

• SIMATIC ProTool and SIMATIC ProTool/Lite are modern tools for configuring 

SIMATIC operator panels (OPs) and SIMATIC C7 compact devices. 

• ProAgent is a diagnostics software that acquires information on the location and 

cause of errors in plants and machinery and thus offers fast and aimed process 

diagnostics. 

 

 

 


A5E00706944-01 1-19



1-20 A5E00706944-01

2 Installation 

2.1 Automation License Manager 

2.1.1 User Rights Through The Automation License Manager 

Automation License Manager 

To use STEP 7 programming software, you require a product-specific license key 

(user rights). Starting with STEP 7 V5.3, this key is installed with the Automation 

License Manager. 

The Automation License Manager is a software product from Siemens AG. It is 

used to manage the license keys (license modules) for all systems. 

The Automation License Manager is located in the following places: 

• On the installation device for a software product requiring a license key 

• On a separate installation device 

• As a download from the Internet page of A&D Customer Support at Siemens 

AG 

The Automation License Manager has its own integrated online help. To obtain 

help after the license manager is installed, press F1 or select the Help > Help on 

License Manager. This online help contains detailed information on the 

functionality and operation of the Automation License Manager. 

Licenses 

Licenses are required to use STEP 7 program packages whose legal use is 

protected by licenses. A license gives the user a legal right to use the product. 

Evidence of this right is provided by the following: 

• The CoL (Certificate of License), and 

• The license key 

Certificate of License (CoL) 

The "Certificate of License" that is included with a product is the legal evidence that 

a right to use this product exists. This product may only be used by the owner of 

the Certificate of License (CoL) or by those persons authorized to do so by the 

owner. 


A5E00706944-01 2-1

Installation 

License Keys 

The license key is the technical representation (an electronic "license stamp") of a 

license to use software. 

SIEMENS AG issues a license key for all of its software that is protected by a 

license. When the computer has been started, such software can only be used in 

accordance with the applicable license and terms of use after the presence of a 

valid license key has been verified. 

Notes 

• You can use the standard software without a license key to familiarize yourself 

with the user interface and functions. 

• However, a license is required and necessary for full, unrestricted use of the 

STEP 7 software in accordance with the license agreement 

• If you have not installed the license key, you will be prompted to do so at 

regular intervals. 

License Keys can be stored and transferred among various types of storage 

devices as follows: 

• On license key diskettes 

• On the local hard disk 

• On network hard disk 

If software products for which no license is available are installed, you can then 

determine which license key is needed and order it as required. 

For further information on obtaining and using license keys, please refer to the 

online help for the Automation License Manager. 


2-2 A5E00706944-01

Installation 

Types of Licenses 

The following different types of application-oriented user licenses are available for 

software products from Siemens AG. The actual behavior of the software is 

determined by which type license key is installed for it. The type of use can be 

found on the accompanying Certificate of License. 

License Type 

Single License 

Floating License 

Trial License 

Rental License 

Upgrade License 

Description 

The software can be used on any single computer desired for an unlimited 

amount of time. 

The software can be used on a computer network ("remote use") for an 

unlimited amount of time. 

The software can be used subject to the following restrictions: 

• A period of validity of up to a maximum of 14 days, 

• A total number of operating days after the day of first use, 

• A use for tests and validation (exemption from liability). 

The software can be used subject to the following restrictions: 

• A period of validity of up to a maximum of 50 days 

• A total number of operating hours of use 

Certain requirements in the existing system may apply with regard to software 

upgrades: 

• An upgrade license may be used to convert an "old version X" of the 

software to a newer version X+. 

• An upgrade may be necessary due to an increase in the volume of data 

being handled in the given system. 


A5E00706944-01 2-3

Installation 

2.1.2 Installing the Automation License Manager 

The Automation License Manager is installed by means of an MSI setup process. 

The installation software for the Automation License Manager is included on the 

STEP 7 product CD. 

You can install the Automation License Manager at the same time you install 

STEP 7 or at a later time. 

Notes 

• For detailed information on how to install the Automation License Manager, 

please refer to the current "Readme.wri" file 

• The online help for the Automation License Manager contains all the 

information you need on the function and handling of License Keys. 

Subsequent installation of license keys 

If you start the STEP 7 software and no license keys are available, a warning 

message indicating this condition will be displayed. 

Notes 

• You can use the standard software without a license key to familiarize yourself 

with the user interface and functions. 

• However, a license is required and necessary for full, unrestricted use of the 

STEP 7 software in accordance with the license agreement 

• If you have not installed the license key, you will be prompted to do so at 

regular intervals. 

You can subsequently install license keys in the following ways: 

• Install license keys from diskettes 

• Install license keys downloaded from the Internet. In this case, the license keys 

must be ordered first. 

• Use floating license keys available in a network 

For detailed information on installing license keys, refer to the online help for the 

Automation License Manager. To access this help, press F1 or select the Help > 

Help on License Manager menu command. 

Notes 

• In Windows 2000/XP/Server 2003, license keys will only be operational if they 

are installed on a local hard disk and have write-access status. 

• Floating licenses can also be used within a network ("remote" use). 


2-4 A5E00706944-01

Installation 

2.1.3 Guidelines for Handling License Keys 

! 

Caution 

Please note the information on handling license keys that is available in the online 

help on the Automation License Manager and also in the STEP 7 Readme.wri file 

on the installation CD-ROM. If you do not follow these guidelines, the license keys 

may be irretrievably lost. 

To access online help for the Automation License Manager, press F1 for contextsensitive 

help or select the Help > Help on License Manager menu command. 

This help section contains all the information you need on the function and 

handling of license keys. 


A5E00706944-01 2-5

Installation 

2.2 Installing STEP 7 

The STEP 7 Setup program performs an automatic installation. The complete 

installation procedure is menu controlled. Execute Setup using the standard 

Windows 2000/XP/Server 2003 software installation procedure. 

The major stages in the installation are: 

• Copying the data to your programming device 

• Configuration of EPROM and communication drivers 

• Installing the license keys (if desired) 

Note 

Siemens programming devices are shipped with the STEP 7 software on the hard 

disk ready for installation. 

Installation requirements 

• Operating system: 

Microsoft Windows 2000 or Windows XP, Windows Server 2003. 

• Basic hardware: 

Programming device or PC with: 

• Pentium processor (600 MHz) 

• At least 256 MB RAM. 

• Color monitor, keyboard and mouse, all of which are supported by Microsoft 

Windows 

A programming device (PG) is a PC with a special compact design for industrial 

use. It is fully equipped for programming SIMATIC PLCs. 

• Hard disk space: 

Refer to the "README.WRI" file for information on required hard disk space. 

• MPI interface (optional): 

An MPI interface is only required to interconnect the PG/PC and the PLC if you 

want to use it for communication with the PLC under STEP 7. 

In this case you require: 

• A PC USB adapter that is connected to the communications port of your device, 

or 

• An MPI module (for example, CP 5611) that is installed in your device. 


2-6 A5E00706944-01

Installation 

PGs are supplied with an MPI interface. 

• External prommer (optional) 

An external prommer is only required if you want to program EPROMs with a 

PC. 

Note 

Refer to the information on STEP 7 installation in the README.WRI file and the 

"List of SIMATIC Software Packages compatible to the versions of the standard 

STEP 7 software package." 

You can find the Readme file in the start menu under Start > Simatic > Product 

Notes. 

The compatibility list is found via the Start menu, under Start > Simatic > 

Documentation. 


A5E00706944-01 2-7

Installation 

2.2.1 Installation Procedure 

Preparing for Installation 

The operating system (Windows 2000, XP or Server 2003) must be started before 

you can start your software installation. 

• You do not require an external storage medium if the installable STEP 7 

software is already stored on the hard disk of the PG. 

• To install from CD-ROM, insert the CD-ROM in the CD-ROM drive of your PC. 

Starting the Installation Program 

To install the software, proceed as follows: 

1. Insert the CD-ROM and double click on the file "SETUP.EXE". 

2. Follow the on-screen step-by-step instructions of the installation program. 

The program guides you through all steps of the installation. You can go to the next 

step or return to the previous step. 

During installation, the dialog boxes prompt you to make your choice from the 

displayed options. The following notes will help you to quickly and easily find the 

right answers. 

If a Version of STEP 7 Is Already Installed... 

If Setup detects another version of STEP 7 on the programming device, a 

corresponding message is displayed. You can then choose to: 

• Abort the installation (so that you can uninstall the old STEP 7 version under 

Windows and then restart Setup, or 

• Continue Setup and overwrite the previous version. 

For well organized software management you should always uninstall any older 

versions before installing the new version. the disadvantage of overwriting previous 

versions with a new version is that when you subsequently uninstall the old 

software version some components of the old version may not be removed. 

Selecting the Installation Options 

You have three was to select the scope of the installation: 

• Standard setup: all dialog languages for the user interface, all applications, and 

all examples. Refer to the current Product Information for information on 

memory space required for this type of configuration. 

• Basic setup: only one dialog language, no examples. Refer to the current 

Product Information for information on memory space required for this type of 

configuration. 

• User-defined ("custom") setup: you can determine the scope of the installation, 

e.g. the programs, databases, examples, and communication functions. 


2-8 A5E00706944-01

Installation 

ID Number 

You will be prompted during setup to enter an ID number (found on the Software 

Product Certificate or on your license key diskette). 

Installing License Keys 

During setup, the program checks to see whether a corresponding license key is 

installed on the hard disk. If no valid license key is found, a message stating that 

the software can be used only with a license key is displayed. If you want, you can 

install the license key immediately or continue setup and then install the key later. If 

you want to install the license key now, insert the authorization diskette when 

prompted to do so. 

PG/PC Interface Settings 

During installation, a dialog box is displayed where you can assign parameters to 

the programming device/PC interface. You will find more information on it in 

"Setting the PG/PC Interface." 

Assigning Parameters to Memory Cards 

During installation, a dialog box is displayed where you can assign parameters to 

Memory Cards. 

• You do not need an EPROM driver if you are not using any Memory Cards. 

Select the option "No EPROM Driver". 

• Otherwise, select the entry which applies to your PG. 

• If you are using a PC, you can select a driver for an external prommer. Here 

you must specify the port to which the prommer is connected (for example, 

LPT1). 

You can change the set parameters after installation by calling the program 

"Memory Card Parameter Assignment" in the STEP 7 program group or in the 

Control Panel. 

Flash-File Systems 

In the dialog box for assigning memory card parameters, you can select to install a 

flash-file system. 

The flash-file system is required, for example under SIMATIC M7 when you write 

individual files to an EPROM memory card without changing other contents of the 

Memory Card. 

If you are using a suitable programming device (PG 720/PG 740/PG 760, Field PG 

and Power PG) or external prommer and you want to use this function, install the 

flash-file system. 


A5E00706944-01 2-9

Installation 

If Errors Occur during the Installation 

Setup may be cancelled due to the following errors: 

• If an initialization error occurs immediately after the start of Setup, more than 

likely setup was not started under Windows. 

• Insufficient hard disk space: Minimum free hard disk space required for a 

standard software installation is 100 Mbytes, regardless of the scope of your 

installation. 

• Bad CD-ROM: If the CD is faulty, please contact your local Siemens 

representative. 

• Operator error: Restart setup follow the instructions carefully. 

After the installation has been completed… 

An on-screen message reports the successful installation. 

If any changes were made to system files during the installation, you are prompted 

to restart Windows. After this restart (warm restart) you can start the STEP 7 

application, the SIMATIC Manager. 

After successful installation, a program group for STEP 7 has been set up. 


2-10 A5E00706944-01

Installation 

2.2.2 Setting the PG/PC Interface 

Here you configure the communication between the PG/PC and the PLC. During 

installation, you are displayed a dialog for assigning parameters to the PG/PC 

interface. You can also open this dialog box after installation, by calling the 

program "Setting PG/PC Interface" in the STEP 7 program group. This enables you 

to modify the interface parameters at a later time, independently of the installation. 

Basic Procedure 

To operate an interface, you will require the following: 

• Configurations in the operating system 

• A suitable interface configuration 

If you are using a PC with an MPI card or communications processors (CP), you 

should check the interrupt and address assignments in the Windows "Control 

Panel" to ensure that there are no interrupt conflicts and no address areas overlap. 

In Windows 2000, Windows XP and Server 2003, the ISA component MPI-ISA card 

is no longer supported and therefore no longer offered for installation. 

In order to make it easier to assign parameters to the programming device/PC 

interface, a dialog box will display a selection list of default basic parameter sets 

(interface configurations). 

Assigning Parameters to the PG/PC Interface 

Procedure (Detail are found in the Online Help): 

1. Double-click on "Setting PG/PC Interface" in the "Control Panel" of Windows. 

2. Set the "Access Point of Application" to "S7ONLINE." 

3. In the list "Interface parameter set used", select the required interface 

parameter set. If the required interface parameter set is not displayed, you 

must first install a module or protocol via the "Select" button. The interface 

parameter set is then generated automatically. On plug-and-play systems, you 

can not install plug and play CPs manually (CP 5611 and CP 5511). They are 

integrated automatically in "Setting PG/PC Interface" after you have installed 

the hardware in your PG/PC. 

- If you select an interface which is capable of automatic recognition of 

bus parameters (for example, CP 5611 (Auto)), you can connect the 

programming device or the PC to the MPI or PROFIBUS without having to 

set bus parameters. If the transmission rate is < 187.5 Kbps, there may be 

a delay of up to one minute while the bus parameters are read. 

Requirement for automatic recognition: Masters who broadcast bus 

parameters cyclically are connected to the bus. All new MPI components 

do this; for PROFIBUS subnets the cyclic broadcast of bus parameters 

must be enabled (default PROFIBUS network setting). 

- If you select an interface which does not automatically recognize the 

bus parameters, you can display the properties and adapt them to match 

the subnet. 


A5E00706944-01 2-11

Installation 

Changes will also be necessary if conflicts with other settings arise (for example, 

interrupt or address assignments). In this case, make the appropriate changes with 

the hardware recognition and Control Panel in Windows (see below). 

! 

Caution 

Do not remove any "TCP/IP" parameters from your interface configuration. 

This could cause malfunctioning of other applications. 

Checking the Interrupt and Address Assignments 

If you use a PC with an MPI card, you should always check whether the default 

interrupt and the default address area are free. 


2-12 A5E00706944-01

Installation 

2.3 Uninstalling STEP 7 

Use the standard Windows method to uninstall STEP 7: 

1. Double-click on the "Add/Remove Programs" icon in the "Control Panel." to 

start the Windows software installation dialog box. 

2. Select the STEP 7 entry in the displayed list of installed software. Click the 

button to "Add/Remove" the software. 

3. If the "Remove Shared File" dialog box appears, click the "No" button if you are 

uncertain. 


A5E00706944-01 2-13

Installation 


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3 Working Out the Automation Concept 

3.1 Basic Procedure for Planning an Automation Project 

This chapter outlines the basic tasks involved in planning an automation project for 

a programmable controller (PLC). Based on an example of automating an industrial 

blending process, you are guided step by step through the procedure. 

There are many ways of planning an automation project. The basic procedure that 

you can use for any project is illustrated in the following figure. 

 

 

 

 

 


A5E00706944-01 3-1

Working Out the Automation Concept 

3.2 Dividing the Process into Tasks and Areas 

An automation process consists of a number of individual tasks. By identifying 

groups of related tasks within a process and then breaking these groups down into 

smaller tasks, even the most complex process can be defined. 

The following example of an industrial blending process can be used to illustrate 

how to organize a process into functional areas and individual tasks: 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


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Determining the Areas of a Process 

After defining the process to be controlled, divide the project into related groups or 

areas: 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

As each group is divided into smaller tasks, the tasks required for controlling that 

part of the process become less complicated. 

In our example of an industrial blending process you can identify four distinct areas 

(see table below). In this example, the area for ingredient A contains the same 

equipment as the area for ingredient B. 

Functional Area 

Ingredient A 

Ingredient B 

Mixing tank 

Drain 

Equipment Used 

Feed pump for ingredient A 

Inlet valve for ingredient A 

Feed valve for ingredient A 

Flow sensor for ingredient A 

Feed pump for ingredient B 

Inlet valve for ingredient B 

Feed valve for ingredient B 

Flow sensor for ingredient B 

Agitator motor 

Switch for tank level measurement 

Drain valve 


A5E00706944-01 3-3


3.3 Describing the Individual Functional Areas 

As you describe each area and task within your process, you define not only the 

operation of each area, but also the various elements that control the area. These 

include: 

• Electrical, mechanical, and logical inputs and outputs for each task 

• Interlocks and dependencies between the individual tasks 

The sample industrial blending process uses pumps, motors, and valves. These 

must be described precisely to identify the operating characteristics and type of 

interlocks required during operation. The following tables provide examples of the 

description of the equipment used in an industrial blending process. When you 

have completed description, you could also use it to order the required equipment. 

Ingredients A/B: Feed Pump Motors 

The feed pump motors convey ingredients A and B to the mixing tank. 

• Flow rate: 400 l (100 gallons) per minute 

• Rating: 100 kW (134 hp) at 1200 rpm 

The pumps are controlled (start/stop) from an operator station located near the mixing tank. The number 

of starts is counted for maintenance purposes. Both the counters and the display can be reset with one 

button. 

The following conditions must be satisfied for the pumps to operate: 

• The mixing tank is not full. 

• The drain valve of the mixing tank is closed. 

• The emergency off is not activated. 

The pumps are switched off if the following condition is satisfied: 

• The flow sensor signals no flow 7 seconds after the pump motor is started. 

• The flow sensor signals that the flow has ceased. 

Ingredients A/B: Inlet and Feed Valves 

The inlet and feed valves for ingredients A and B allow or prevent the flow of the ingredients into the 

mixing tank. The valves have a solenoid with a spring return. 

• When the solenoid is activated, the valve is opened. 

• When the solenoid is deactivated, the valve is closed. 

The inlet and feed valves are controlled by the user program. 

For the valves to be activated, the following condition must be satisfied: 

• The feed pump motor has been running for at least 1 second. 


• The flow sensor signals no flow. 


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Agitator Motor 

The agitator motor mixes ingredient A with ingredient B in the mixing tank. 

• Rating: 100 kW (134 hp) at 1200 rpm 

The agitator motor is controlled (start/stop) from an operator station located near the mixing tank. The 

number of starts is counted for maintenance purposes. Both the counters and the display can be reset 

with one button. 

The following conditions must be satisfied for the pumps to operate: 

• The tank level sensor is not signaling "Tank below minimum." 

• The drain valve of the mixing tank is closed. 



• The tachometer does not indicate that the rated speed has been reached within 10 seconds of 

starting the motor. 

Drain Valve 

The drain valve allows the mixture to drain (using gravity feed) to the next stage in the process. The 

valve has a solenoid with a spring return. 

• If the solenoid is activated, the outlet valve is opened. 

• If the solenoid is deactivated, the outlet valve is closed. 

The outlet valve is controlled (open/close) from an operator station. 

The drain valve can be opened under the following conditions: 

• The agitator motor is off. 

• The tank level sensor is not signaling "Tank empty." 



• The tank level sensor is indicating "Tank empty." 

Switches for Tank Level Measurement 

The switches in the mixing tank indicate the level in the tank and are used to interlock the feed pumps 

and the agitator motor. 


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3.4 Listing Inputs, Outputs, and In/Outs 

After writing a physical description of each device to be controlled, draw diagrams 

of the inputs and outputs for each device or task area. 

 

 

 

 

 

 

 

 

These diagrams correspond to the logic blocks to be programmed. 

3.5 Creating an I/O Diagram for the Motors 

Two feed pumps and one agitator are used in our example of an industrial blending 

process. Each motor is controlled by its own "motor block" that is the same for all 

three devices. This block requires six inputs: two to start or stop the motor, one to 

reset the maintenance display, one for the motor response signal (motor running / 

not running), one for the time during which the response signal must be received, 

and one for the number of the timer used to measure the time. 

The logic block also requires four outputs: two to indicate the operating state of the 

motor, one to indicate faults, and one to indicate that the motor is due for 

maintenance. 

An in/out is also necessary to activate the motor. It is used to control the motor but 

at the same time is also edited and modified in the program for the "motor block." 

 

 

 

 

 

 

 

 

 

 

 

 

 


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3.6 Creating an I/O Diagram for the Valves 

Each valve is controlled by its own "valve block" that is the same for all valves 

used. The logic block has two inputs: one to open the valve and one to close the 

valve. It also has two outputs: one to indicate that the valve is open and the other 

to indicate that it is closed. 

The block has an in/out to activate the valve. It is used to control the valve but at 

the same time is also edited and modified in the program for the "valve block." 

 

 

 

 

 

 

 


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3.7 Establishing the Safety Requirements 

Decide which additional elements are needed to ensure the safety of the process - 

based on legal requirements and corporate health and safety policy. In your 

description, you should also include any influences that the safety elements have 

on your process areas. 

Defining Safety Requirements 

Find out which devices require hardwired circuits to meet safety requirements. By 

definition, these safety circuits operate independently of the programmable 

controller (although the safety circuit generally provides an I/O interface to allow 

coordination with the user program). Normally, you configure a matrix to connect 

every actuator with its own emergency off range. This matrix is the basis for the 

circuit diagrams of the safety circuits. 

To design safety mechanisms, proceed as follows: 

• Determine the logical and mechanical/electrical interlocks between the 

individual automation tasks. 

• Design circuits to allow the devices belonging to the process to be operated 

manually in an emergency. 

• Establish any further safety requirements for safe operation of the process. 

Creating a Safety Circuit 

The sample industrial blending process uses the following logic for its safety circuit: 

• One emergency off switch shuts down the following devices independent of the 

programmable controller (PLC): 

- Feed pump for ingredient A 

- Feed pump for ingredient B 

- Agitator motor 

- Valves 

• The emergency off switch is located on the operator station. 

• An input to the controller indicates the state of the emergency off switch. 


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3.8 Describing the Required Operator Displays and 

Controls 

Every process requires an operator interface that allows human intervention in the 

process. Part of the design specification includes the design of the operator 

console. 

Defining an Operator Console 

In the industrial blending process described in our example, each device can be 

started or stopped by a pushbutton located on the operator console. This operator 

console includes indicators to show the status of the operation (see figure below). 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The console also includes display lamps for the devices that require maintenance 

after a certain number of starts and the emergency off switch with which the 

process can be stopped immediately. The console also has a reset button for the 

maintenance display of the three motors. Using this, you can turn off the 

maintenance display lamps for the motors due for maintenance and reset the 

corresponding counters to 0. 


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3.9 Creating a Configuration Diagram 

After you have documented the design requirements, you must then decide on the 

type of control equipment required for the project. 

By deciding which modules you want to use, you also specify the structure of the 

programmable controller. Create a configuration diagram specifying the following 

aspects: 

• Type of CPU 

• Number and type of I/O modules 

• Configuration of the physical inputs and outputs 

The following figure illustrates an example of an S7 configuration for the industrial 

blending process. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


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4 Basics of Designing a Program Structure 

4.1 Programs in a CPU 

A CPU will principally run two different programs: 

• The operating system and 

• The user program. 

Operating System 

Every CPU comes with an integrated operating system that organizes all CPU 

functions and sequences not associated with a specific control task. The tasks of 

the operating system include the following: 

• Handling restart (warm start) and hot restart 

• Update of the process image table of the inputs and output of the process 

image table of the outputs 

• Calling the user program 

• Acquisition of interrupt information and calling interrupt OBs 

• Recognition of errors and error handling 

• Management of the memory areas 

• Communication with programming devices and other communication partners 

You can influence CPU reactions in certain areas by modifying the operating 

system parameters (operating system default settings). 

User Program 

You create the user program and download it to the CPU. It contains all the 

functions required to process your specific automation task. The tasks of the user 

program include: 

• Specifying the conditions for a restart (warm start) and hot restart on the CPU 

(for example, initializing signals with a particular value) 

• Processing process data (for example, generating logical links of binary signals, 

fetching and evaluating analog signals, specifying binary signals for output, 

output of analog values) 

• Reaction to interrupts 

• Handling disturbances in the normal program cycle. 


A5E00706944-01 4-1

Basics of Designing a Program Structure 

4.2 Blocks in the User Program 

The STEP 7 programming software allows you to structure your user program, in 

other words to break down the program into individual, self-contained program 

sections. This has the following advantages: 

• Extensive programs are easier to understand. 

• Individual program sections can be standardized. 

• Program organization is simplified. 

• It is easier to make modifications to the program. 

• Debugging is simplified since you can test separate sections. 

• Commissioning your system is made much easier. 

The example of an industrial blending process illustrated the advantages of 

breaking down an automation process into individual tasks. The program sections 

of a structured user program correspond to these individual tasks and are known 

as the blocks of a program 

Block Types 

There are several different types of blocks you can use within an S7 user program: 

Block Brief Description of Function See Also 

Organization blocks (OB) 

System function blocks 

(SFB) and system 

functions (SFC) 

Function blocks (FB) 

Functions (FC) 

Instance data blocks 

(instance DB) 

Data blocks (DB) 

OBs determine the structure of the user 

program. 

SFBs and SFCs are integrated in the S7 CPU 

and allow you access to some important 

system functions. 

FBs are blocks with a "memory" which you 

can program yourself. 

FCs contain program routines for frequently 

used functions. 

Instance DBs are associated with the block 

when an FB/SFB is called. They are created 

automatically during compilation. 

DBs are data areas for storing user data. In 

addition to the data that are assigned to a 

function block, shared data can also be 

defined and used by any blocks. 

Organization Blocks and 

Program Structure 

System Function Blocks 

(SFB) and System 

Functions (SFC) 

Function Blocks (FB) 

Functions (FC) 

Instance Data Blocks 

Shared Data Blocks (DB) 

OBs, FBs, SFBs, FCs, and SFCs contain sections of the program and are therefore 

also known as logic blocks. The permitted number of blocks per block type and the 

permitted length of the blocks is CPU-specific. 


4-2 A5E00706944-01


4.2.1 Organization Blocks and Program Structure 

Organization blocks (OBs) represent the interface between the operating system 

and the user program. Called by the operating system, they control cyclic and 

interrupt-driven program execution, startup behavior of the PLC and error handling. 

You can program the organization blocks to determine CPU behavior. 

Organization Block Priority 

Organization blocks determine the sequence (start events) by which individual 

program sections are executed. An OB call can interrupt the execution of another 

OB. Which OB is allowed to interrupt another OB depends on its priority. Higher 

priority OBs can interrupt lower priority OBs. The background OB has the lowest 

priority. 

Types of Interrupt and Priority Classes 

Start events triggering an OB call are known as interrupts. The following table 

shows the types of interrupt in STEP 7 and the priority of the organization blocks 

assigned to them. Not all organization blocks listed and their priority classes are 

available in all S7 CPUs (see "S7-300 Programmable Controller, Hardware and 

Installation Manual" and "S7-400, M7-400 Programmable Controllers Module 

Specifications Reference Manual"). 

Type of 

Interrupt 

Main program 

scan 

Time-of-day 

interrupts 

Time-delay 

interrupts 

Cyclic interrupts 

Organization Block 

Priority Class 

(Default) 

See also 

OB1 1 Organization Block for Cyclic 

Program Processing (OB1) 

OB10 to OB17 2 Time-of-Day Interrupt Organization 

Blocks (OB10 to OB17) 

OB20 

3 

Time-Delay Interrupt Organization 

OB21 

4 


OB22 

5 

OB23 

6 

OB30 

7 

Cyclic Interrupt Organization Blocks 

OB31 

8 

(OB30 to OB38) 

OB32 

9 

OB33 

10 

OB34 

11 

OB35 

12 

OB36 

13 

OB37 

14 

OB38 

15 


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Type of 

Interrupt 

Hardware OB40 

interrupts OB41 

OB42 

OB43 

OB44 

OB45 

OB46 

OB47 

DPV1 interrupts OB 55 

OB 56 

OB 57 

Multicomputing 

interrupt 

Synchronous 

cycle interrupt 

Redundancy 

errors 

Asynchronous 

errors 

Background 

cycle 

Startup 

Synchronous 

errors 

Organization Block 

Priority Class 

(Default) 

16 

17 

18 

19 

20 

21 

22 

23 

2 

2 

2 

See also 

Hardware Interrupt Organization 


Programming DPV1 Devices 

OB60 Multicomputing 25 Multicomputing - Synchronous 

Operation of Several CPUs 

OB 61 

25 Configuring Short and Equal-Length 

OB 62 

Process Reaction Times on 

OB 63 

PROFIBUS-DP 

OB 64 

OB70 I/O Redundancy Error 

(only in H systems) 

OB72 CPU Redundancy 

Error (only in H systems) 

OB80 Time Error 

OB81 Power Supply Error 

OB82 Diagnostic Interrupt 

OB83 Insert/Remove 

Module Interrupt 

OB84 CPU Hardware Fault 

OB 85 Program Cycle Error 

OB86 Rack Failure 

OB87 Communication Error 

25 

28 

25 

(or 28 if the 

asynchronous 

error OB exists in 

the startup 

program) 

"Error Handling Organization 

Blocks (OB70 to OB87 / OB121 to 

OB122)" 

Error Handling Organization Blocks 

(OB70 to OB87 / OB121 to OB122) 

OB90 29 1) Background Organization Block 

(OB90) 

OB100 Restart 

(Warm start) 

OB101 Hot Restart 

OB102 Cold Restart 

OB121 Programming Error 

OB122 Access Error 

27 

27 

27 

Priority of the OB 

that caused the 

error 

Startup Organization Blocks 

(OB100/OB101/OB102) 

Error Handling Organization Blocks 

(OB70 to OB87 / OB121 to OB122) 

1) The priority class 29 corresponds to priority 0.29. The background cycle has a lower priority than the 

free cycle. 


4-4 A5E00706944-01


Changing the Priority 

Interrupts can be assigned parameters with STEP 7. With the parameter 

assignment you can for example, deselect interrupt OBs or priority classes in the 

parameter blocks: time-of-day interrupts, time-delay interrupts, cyclic interrupts, 

and hardware interrupts. 

The priority of organization blocks on S7-300 CPUs is fixed. 

With S7-400 CPUs (and the CPU 318) you can change the priority of the following 

organization blocks with STEP 7: 

• OB10 to OB47 

• OB70 to OB72 (only H CPUs) and OB81 to OB87 in RUN mode. 

The following priority classes are permitted: 

• Priority classes 2 to 23 for OB10 to OB47 

• Priority classes 2 to 28 for OB70 to OB72 

• Priority classes 24 to 26 for OB81 to OB87; for CPUs as of approx. The middle 

of 2001 (Firmware Version 3.0) the ranges where extended: Priority classes 2 to 

26 can be set for OB 81 to OB 84 as well as for OB 86 and OB 87. 

You can assign the same priority to several OBs. OBs with the same priority are 

processed in the order in which their start events occur. 

Error OBs started by synchronous errors are executed in the same priority class as 

the block being executed when the error occurred. 

Local Data 

When creating logic blocks (OBs, FCs, FBs), you can declare temporary local data. 

The local data area on the CPU is divided among the priority classes. 

On S7-400, you can change the amount of local data per priority class in the 

"priority classes" parameter block using STEP 7. 

Start Information of an OB 

Every organization block has start information of 20 bytes of local data that the 

operating system supplies when an OB is started. The start information specifies 

the start event of the OB, the date and time of the OB start, errors that have 

occurred, and diagnostic events. 

For example, OB40, a hardware interrupt OB, contains the address of the module 

that generated the interrupt in its start information. 


A5E00706944-01 4-5


Deselected Interrupt OBs 

If you assign priority class 0 or assign less than 20 bytes of local data to a priority 

class, the corresponding interrupt OB is deselected. The handling of deselected 

interrupt OBs is restricted as follows: 

• In RUN mode, they cannot be copied or linked into your user program. 

• In STOP mode, they can be copied or linked into your user program, but when 

the CPU goes through a restart (warm start) they stop the startup and an entry 

is made in the diagnostic buffer. 

By deselecting interrupt OBs that you do not require, you increase the amount of 

local data area available, and this can be used to save temporary data in other 

priority classes. 

Cyclic Program Processing 

Cyclic program processing is the "normal" type of program execution on 

programmable logic controllers, meaning the operating system runs in a program 

loop (the cycle) and calls the organization block OB1 once in every loop in the main 

program. The user program in OB1 is therefore executed cyclically. 

 

 

 

 

 

 


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Event-Driven Program Processing 

Cyclic program processing can be interrupted by certain events (interrupts). If such 

an event occurs, the block currently being executed is interrupted at a command 

boundary and a different organization block that is assigned to the particular event 

is called. Once the organization block has been executed, the cyclic program is 

resumed at the point at which it was interrupted. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This means it is possible to process parts of the user program that do not have to 

be processed cyclically only when needed. The user program can be divided up 

into "subroutines" and distributed among different organization blocks. If the user 

program is to react to an important signal that occurs relatively seldom (for 

example, a limit value sensor for measuring the level in a tank reports that the 

maximum level has been reached), the subroutine that is to be processed when the 

signal is output can be located in an OB whose processing is event-driven. 


A5E00706944-01 4-7


Linear Versus Structured Programming 

You can write your entire user program in OB1 (linear programming). This is only 

advisable with simple programs written for the S7-300 CPU and requiring little 

memory. 

Complex automation tasks can be controlled more easily by dividing them into 

smaller tasks reflecting the technological functions of the process or that can be 

used more than once. These tasks are represented by corresponding program 

sections, known as the blocks (structured programming). 

 

 

 

 

 

 

 

 


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4.2.2 Call Hierarchy in the User Program 

For the user program to function, the blocks that make up the user program must 

be called. This is done using special STEP 7 instructions, the block calls, that can 

only be programmed and started in logic blocks. 

Order and Nesting Depth 

The order and nesting of the block calls is known as the call hierarchy. The number 

of blocks that can be nested (the nesting depth) depends on the particular CPU. 

The following figure illustrates the order and nesting depth of the block calls within 

a scan cycle. 

 

 

 

 

 

 

 

 

 

 

There is a set order for creating blocks: 

• You create the blocks from top to bottom, so you start with the top row of 

blocks. 

• Every block that is called must already exist, meaning that within a row of 

blocks the order for creating them is from right to left. 

• The last block to be created is OB1. 

Putting these rules into practice for the example in the figure produces the following 

sequence for creating the blocks: 

FC1 > FB1 + instance DB1 > DB1 > SFC1 > FB2 + instance DB2 > OB1 

Note 

If the nesting is too deep (too many levels), the local data stack may overflow (Also 

refer to Local Data Stack). 


A5E00706944-01 4-9


Block Calls 

The following figure shows the sequence of a block call within a user program. The 

program calls the second block whose instructions are then executed completely. 

Once the second or called block has been executed, execution of the interrupted 

block that made the call is resumed at the instruction following the block call. 

 

 

 

 

 

 

 

 

 

 

 

Before you program a block, you must specify which data will be used by your 

program, in other words, you must declare the variables of the block. 

Note 

OUT parameters must be described for each block call. 

Note 

The operating system resets the instances of SFB3 "TP" when a cold restart is 

performed. If you want to initialize instances of this SFB after a cold restart, you 

must call up the relevant instances of the SFB with PT = 0 ms via OB100. You can 

do this, for example, by performing an initialization routine in the blocks which 

contain instances of the SFB. 


4-10 A5E00706944-01


4.2.3 Block Types 

4.2.3.1 Organization Block for Cyclic Program Processing (OB1) 

Cyclic program processing is the ”normal" type of program execution on 

programmable logic controllers. The operating system calls OB1 cyclically and with 

this call it starts cyclic execution of the user program. 

Sequence of Cyclic Program Processing 

The following table shows the phases of cyclic program processing: 

Step Sequence in CPUs to 10/98 Sequence in CPUs from 10/98 

1 The operating system starts the cycle 

monitoring time. 

2 The CPU reads the state of the inputs of the 

input modules and updates the process image 

table of the inputs. 

3 The CPU processes the user program and 

executes the instructions contained in the 

program. 

4 The CPU writes the values from the process 

image table of the outputs to the output 

modules. 

5 At the end of a cycle, the operating system 

executes any tasks that are pending, for 

example downloading and deleting blocks, 

receiving and sending global data. 

6 Finally, the CPU returns to the start of the 

cycle and restarts the cycle monitoring time. 

The operating system starts the cycle 

monitoring time. 

The CPU writes the values from the process 

image table of the outputs to the output 

modules. 

The CPU reads the state of the inputs of the 

input modules and updates the process image 

table of the inputs. 

The CPU processes the user program and 

executes the instructions contained in the 

program. 

At the end of a cycle, the operating system 

executes any tasks that are pending, for 

example downloading and deleting blocks, 

receiving and sending global data. 

Finally, the CPU returns to the start of the 

cycle and restarts the cycle monitoring time. 

Process Images 

So that the CPU has a consistent image of the process signals during cyclic 

program processing, the CPU does not address the input (I) and output (Q) 

address areas directly on the I/O modules but rather accesses an internal memory 

area of the CPU that contains an image of the inputs and outputs. 

Programming Cyclic Program Processing 

You program cyclic program processing by writing your user program in OB1 and 

in the blocks called within OB1 using STEP 7. 

Cyclic program processing begins as soon as the startup program is completed 

without errors. 


A5E00706944-01 4-11


Interrupts 

Cyclic program processing can be interrupted by the following: 

• An interrupt 

• A STOP command (mode selector, menu option on the programming device, 

SFC46 STP, SFB20 STOP) 

• A power outage 

• The occurrence of a fault or program error 

Scan Cycle Time 

The scan cycle time is the time required by the operating system to run the cyclic 

program and all the program sections that interrupt the cycle (for example, 

executing other organization blocks) and system activities (for example, updating 

the process image). This time is monitored. 

The scan cycle time (T C ) is not the same in every cycle. The following figures show 

different scan cycle times (T C1 ≠ T C2 ) for CPUs up to 10/98 and CPUs from 10/98: 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In the current cycle, OB1 is interrupted by a Time-Of-Day interrupt. 


4-12 A5E00706944-01


Cycle Monitoring Time 

With STEP 7, you can modify the default maximum cycle monitoring time. If this 

time expires, the CPU either changes to STOP mode or OB80 is called in which 

you can specify how the CPU should react to this error. 

Minimum Cycle Time 

With STEP 7, you can set a minimum cycle time for S7-400 CPUs and the 

CPU 318. This is useful in the following situations: 

• When the interval at which program execution starts in OB1 (main program 

scan) should always be the same or 

• When the process image tables would be updated unnecessarily often if the 

cycle time is too short. 

The following figures show the function of the cycle monitoring time in program 

processing in CPUs up to 10/98 and in CPUs from 10/98. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 4-13


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Updating the Process Image 

During cyclic program processing by the CPU, the process image is updated 

automatically. With the S7-400 CPUs and the CPU 318 you can deselect the 

update of the process image if you want to: 

• Access the I/O directly instead or 

• Update one or more process image input or output sections at a different point 

in the program using system functions SFC26 UPDAT_PI and SFC27 

UPDAT_PO. 

Communication Load 

You can use the CPU parameter "Scan Cycle Load from Communication" to 

control within a given framework the duration of communication processes that 

always increase the scan cycle time. Examples of communication processes 

include transmitting data to another CPU by means of MPI or loading blocks by 

means of a programming device. 

Test functions with a programming device are barely influenced by this parameter. 

However, you can increase the scan cycle time considerably. In the process mode, 

you can limit the time set for test functions (S7-300 only). 


4-14 A5E00706944-01


How the Parameter works 

The operating system of the CPU constantly provides the communication with the 

configured percent of the entire CPU processing capacity (time slice technique). If 

this processing capacity is not needed for the communication, it is available to the 

rest of the processing. 

Effect on the Actual Scan Cycle Time 

Without additional asynchronous events, the OB1 scan cycle time is extended by a 

factor that can be calculated according to the following formula: 

100 

100 - "Scan cycle load from communication (%)" 

Example 1 (no additional asynchronous events): 

When you set the load added to the cycle by communication to 50%, the OB1 scan 

cycle time can be doubled. 

At the same time, the OB1 scan cycle time is also influenced by asynchronous 

events (such as hardware interrupts or cyclic interrupts). From a statistical point of 

view, even more asynchronous events occur within an OB1 scan cycle because of 

the extension of the scan cycle time by the communication portion. This causes an 

additional increase in the OB1 scan cycle. This increase depends on how many 

events occur per OB1 scan cycle and on the duration of event processing. 

Example 2 (additional asynchronous events considered): 

For a pure OB1 execution time of 500 ms, a communication load of 50% can result 

in an actual scan cycle time of up to 1000 ms (provided that the CPU always has 

enough communication jobs to process). If, parallel to this, a cyclic interrupt with 

20 ms processing time is executed every 100 ms, this cyclic interrupt would extend 

the scan cycle by a total of 5*20 ms = 100 ms without communication load. That is, 

the actual scan cycle time would be 600 ms. Because a cyclic interrupt also 

interrupts communication, it affects the scan cycle time by 10 * 20 ms with 50% 

communication load. That is, in this case, the actual scan cycle time amounts to 

1200 ms instead of 1000 ms. 

Note 

• Check the effects of changing the value of the "Scan Cycle Load from 

Communication" parameter while the system is running. 

• The communication load must be taken into account when setting the 

minimum scan cycle time; otherwise time errors will occur. 

Recommendations 

• Where possible, apply the default value. 

• Increase this value only if you are using the CPU primarily for communication 

purposes and your user program is not time critical. 

• In all other cases, only reduce the value. 

• Set the process mode (S7-300 only), and limit the time needed there for test 

functions. 


A5E00706944-01 4-15


4.2.3.2 Functions (FC) 

Functions (FCs) belong to the blocks that you program yourself. A function is a 

logic block "without memory." Temporary variables belonging to the FC are saved 

in the local data stack. This data is then lost when the FC has been executed. To 

save data permanently, functions can also use shared data blocks. 

Since an FC does not have any memory of its own, you must always specify actual 

parameters for it. You cannot assign initial values for the local data of an FC. 

Application 

An FC contains a program section that is always executed when the FC is called 

by a different logic block. You can use functions for the following purposes: 

• To return a function value to the calling block (example: math functions) 

• To execute a technological function (example: single control function with a bit 

logic operation). 

Assigning Actual Parameters to the Formal Parameters 

A formal parameter is a dummy for the "actual" parameter. Actual parameters 

replace the formal parameters when the function is called. You must always assign 

actual parameters to the formal parameters of an FC (for example, an actual 

parameter "I 3.6" to the formal parameter "Start"). The input, output and in/out 

parameters used by the FC are saved as pointers to the actual parameters of the 

logic block that called the FC. 

Important Differences Between the Output Parameters of FCs and FBs 

In function blocks (FB), a copy of the actual parameters in the instance DB is used 

when accessing the parameters. If an input parameter is not transferred or an 

output parameter is not write accessed when a FB is called, the older values still 

stored in the instance DB /Instance DB = memory of the FBs) will be used. 

Functions (FC) have no memory. Contrary to FBs, the assignment of formal 

parameters to these FCs is therefore not optional, but rather essentially. FC 

parameters are accessed via addresses (pointers to targets across area 

boundaries). When an address of the data area (data block) or a local variable of 

the calling block is used as actual parameter, a copy of the actual parameter is 

saved temporarily to local data area of the calling block for the transfer of the 

parameter. 

Caution 

In this case, if no data are written to an OUTPUT parameter in an FC, the block 

may output random values! 

As the calling block's local data area which is reserved for the copy is not assigned 

to the OUTPUT parameter, no data will be written to this area. It will therefore 

remain unchanged and the random value stored at this location will be output, 

because local data are not automatically set to "0" by default, for example. 


4-16 A5E00706944-01


Thus, observe the following points: 

• If possible, initialize the OUTPUT parameters. 

• Set and reset instructions depend on RLO. When these instructions are used to 

determine the value at an OUTPUT parameter, no value is generated if the 

result of a previous logic operation (RLO) = 0. 

• Always ensure that data are written to the OUTPUT parameters - irrespective of 

any program paths in the block. Pay special attention to jump instructions, to the 

ENO output in LAD and FBD as well as to BEC (Block End Conditional) and the 

influence of MCR (Master Control Relay) instructions. 

Note 

Although the OUTPUT parameters of an FB or the INOUT parameters of an FC 

and FB will not output random values (the old output value - or input value as 

output value - is going to be maintained even if no data are written to the 

parameter) you should still observe the points above in order to avoid unintentional 

processing of "old" values. 

4.2.3.3 Function Blocks (FB) 

Function blocks (FBs) belong to the blocks that you program yourself. A function 

block is a block "with memory." It is assigned a data block as its memory (instance 

data block). The parameters that are transferred to the FB and the static variables 

are saved in the instance DB. Temporary variables are saved in the local data 

stack. 

Data saved in the instance DB are not lost when execution of the FB is complete. 

Data saved in the local data stack are, however, lost when execution of the FB is 

completed. 

Note 

To avoid errors when working with FBs, read Permitted Data Types when 

Transferring Parameters in the Appendix. 

Application 

An FB contains a program that is always executed when the FB is called by a 

different logic block. Function blocks make it much easier to program frequently 

occurring, complex functions. 


A5E00706944-01 4-17


Function Blocks and Instance Data Blocks 

An instance data block is assigned to every function block call that transfers 

parameters. 

By calling more than one instance of an FB, you can control more than one device 

with one FB. An FB for a motor type, can, for example, control various motors by 

using a different set of instance data for each different motor. The data for each 

motor (for example, speed, ramping, accumulated operating time etc.) can be 

saved in one or more instance DBs. 

The following figure shows the formal parameters of an FB that uses the actual 

parameters saved in the instance DB. 

 

 

 

 

 

 

 

 

 

 

 

 

 

Variables of the Data Type FB 

If your user program is structured so that an FB contains calls for further already 

existing function blocks, you can include the FBs to be called as static variables of 

the data type FB in the variable declaration table of the calling FB. This technique 

allows you to nest variables and concentrate the instance data in one instance data 

block (multiple instance). 

Assigning Actual Parameters to the Formal Parameters 

It is not generally necessary in STEP 7 to assign actual parameters to the formal 

parameters of an FB. There are, however, exceptions to this. Actual parameters 

must be assigned in the following situations: 

• For an in/out parameter of a complex data type (for example, STRING, ARRAY 

or DATE_AND_TIME) 

• For all parameter types (for example TIMER, COUNTER, or POINTER) 

STEP 7 assigns the actual parameters to the formal parameters of an FB as 

follows: 

• When you specify actual parameters in the call statement: the instructions of the 

FB use the actual parameters provided. 

• When you do not specify actual parameters in the call statement: the 

instructions of the FB use the value saved in the instance DB. 


4-18 A5E00706944-01


The following table shows which variables of the FB must be assigned actual 

parameters. 

Variable 

Data Type 

Elementary Data Type Complex Data Type Parameter Type 

Input No parameter required No parameter required Actual parameter required 

Output No parameter required No parameter required Actual parameter required 

In/out No parameter required Actual parameter 

required 

− 

Assigning Initial Values to Formal Parameters 

You can assign initial values to the formal parameters in the declaration section of 

the FB. These values are written into the instance DB associated with the FB. 

If you do not assign actual parameters to the formal parameters in the call 

statement, STEP 7 uses the values saved in the instance DB. These values can 

also be the initial values that were entered in the variable declaration table of an 

FB. 

The following table shows which variables can be assigned an initial value. Since 

the temporary data are lost after the block has been executed, you cannot assign 

any values to them. 

Variable 

Data Type 

Elementary Data Type Complex Data Type Parameter Type 

Input Initial value permitted Initial value permitted − 

Output Initial value permitted Initial value permitted − 

In/out Initial value permitted − − 

Static Initial value permitted Initial value permitted − 

Temporary − − − 


A5E00706944-01 4-19


4.2.3.4 Instance Data Blocks 

An instance data block is assigned to every function block call that transfers 

parameters. The actual parameters and the static data of the FB are saved in the 

instance DB. The variables declared in the FB determine the structure of the 

instance data block. Instance means a function block call. If, for example, a 

function block is called five times in the S7 user program, there are five instances 

of this block. 

Creating an Instance DB 

Before you create an instance data block, the corresponding FB must already exist. 

You specify the number of the FB when you create the instance data block. 

One Instance DB for Each Separate Instance 

If you assign several instance data blocks to a function block (FB) that controls a 

motor, you can use this FB to control different motors. 

The data for each specific motor (for example, speed, run-up time, total operating 

time) are saved in different data blocks. The DB associated with the FB when it is 

called determines which motor is controlled. With this technique, only one function 

block is necessary for several motors (see the following figure). 

 

 

 

 

 

 

 

 

 

 


4-20 A5E00706944-01


One Instance DB for Several Instances of an FB (Multiple Instances) 

You can also transfer the instance data for several motors at the same time in one 

instance DB. To do this, you must program the calls for the motor controllers in a 

further FB and declare static variables with the data type FB for the individual 

instances in the declaration section of the calling FB. 

If you use one instance DB for several instances of an FB, you save memory and 

optimize the use of data blocks. 

In the following figure, the calling FB is FB21 "Motor processing," the variables are 

of data type FB22, and the instances are identified by Motor_1, Motor_2, and 

Motor_3. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In this example, FB22 does not need its own instance data block, since its instance 

data are saved in the instance data block of the calling FB. 


A5E00706944-01 4-21


One Instance DB for Several Instances of Different FBs (Multiple Instances) 

In a function block you can call the instances of other existing FBs. You can assign 

the instance data required for this to the instance data block of the calling FB, 

meaning you do not need any additional data blocks for the called FBs in this case. 

For these multiple instances in one instance data block, you must declare static 

variables with the data type of the called function block for each individual instance 

in the declaration section of the calling function block. The call within the function 

block does not then require an instance data block, only the symbolic name of the 

variable. 

In the example in this figure, the assigned instance data are stored in a common 

instance DB. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


4-22 A5E00706944-01


4.2.3.5 Shared Data Blocks (DB) 

In contrast to logic blocks, data blocks do not contain STEP 7 instructions. They 

are used to store user data, in other words, data blocks contain variable data with 

which the user program works. Shared data blocks are used to store user data that 

can be accessed by all other blocks. 

The size of DBs can vary. Refer to the description of your CPU for the maximum 

possible size. 

You can structure shared data blocks in any way to suit your particular 

requirements. 

Shared Data Blocks in the User Program 

If a logic block (FC, FB, or OB) is called, it can occupy space in the local data area 

(L stack) temporarily. In addition to this local data area, a logic block can open a 

memory area in the form of a DB. In contrast to the data in the local data area, the 

data in a DB are not deleted when the DB is closed, in other words, after the 

corresponding logic block has been executed. 

Each FB, FC, or OB can read the data from a shared DB or write data to a shared 

DB. This data remains in the DB after the DB is exited. 

A shared DB and an instance DB can be opened at the same time. The following 

figure shows the different methods of access to data blocks. 

 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 4-23


4.2.3.6 System Function Blocks (SFB) and System Functions (SFC) 

Preprogrammed Blocks 

You do not need to program every function yourself. S7 CPUs provide you with 

preprogrammed blocks that you can call in your user program. 

Further information can be found in the reference help on system blocks and 

system functions (Jumps to Language Descriptions and Help on Blocks and 

System Attributes). 

System Function Blocks 

A system function block (SFB) is a function block integrated on the S7 CPU. SFBs 

are part of the operating system and are not loaded as part of the program. Like 

FBs, SFBs are blocks "with memory." You must also create instance data blocks 

for SFBs and download them to the CPU as part of the program. 

S7 CPUs provide the following SFBs: 

• For communication via configured connections 

• For integrated special functions (for example, SFB29 "HS_COUNT" on the 

CPU 312 IFM and the CPU 314 IFM). 

System Functions 

A system function is a preprogrammed function that is integrated on the S7 CPU. 

You can call the SFC in your program. SFCs are part of the operating system and 

are not loaded as part of the program. Like FCs, SFCs are blocks "without 

memory." 

S7 CPUs provide SFCs for the following functions: 

• Copying and block functions 

• Checking the program 

• Handling the clock and run-time meters 

• Transferring data sets 

• Transferring events from a CPU to all other CPUs in multicomputing mode 

• Handling time-of-day and time-delay interrupts 

• Handling synchronous errors, interrupts, and asynchronous errors 

• Information on static and dynamic system data, for example, diagnostics 

• Process image updating and bit field processing 

• Addressing modules 

• Distributed I/O 

• Global data communication 

• Communication via non-configured connections 

• Generating block-related messages 


4-24 A5E00706944-01


Additional Information 

For more detailed information about SFBs and SFCs, refer to the "System 

Software for S7-300 and S7-400, System and Standard Functions" Reference 

Manual. The "S7-300 Programmable Controller, Hardware and Installation Manual" 

and "S7-400, M7-400 Programmable Controllers Module Specifications Reference 

Manual" explain which SFBs and SFCs are available. 


A5E00706944-01 4-25


4.2.4 Organization Blocks for Interrupt-Driven Program Processing 

4.2.4.1 Time-of-Day Interrupt Organization Blocks (OB10 to OB17) 

The S7 CPUs provide the Time-Of-Day interrupt OBs that can be executed at a 

specified date or at certain intervals. 

Time-Of-Day interrupts can be triggered as follows: 

• Once at a particular time (specified in absolute form with the date) 

• Periodically by specifying the start time and the interval at which the interrupt 

should be repeated (for example, every minute, every hour, daily). 

Rules for Time-of-Day Interrupts 

Time-Of-Day interrupts can only be executed when the interrupt has been assigned 

parameters and a corresponding organization block exists in the user program. If 

this is not the case, an error message is entered in the diagnostic buffer and 

asynchronous error handling is executed (OB80, see Error Handling Organization 

Blocks (OB70 to OB87 / OB121 to OB122)). 

Periodic Time-Of-Day interrupts must correspond to a real date. Repeating an 

OB10 monthly starting on January 31st is not possible. In this case, the OB would 

only be started in the months that actually have 31 days (that is, not in February, 

April, June, etc.). 

A Time-Of-Day interrupt activated during startup (restart (warm restart) or hot 

restart) is only executed after the startup is completed. 

Time-Of-Day interrupt OBs that are deselected by the parameter assignment 

cannot be started. The CPU recognizes a programming error and changes to 

STOP mode. 

Following a restart (warm restart), Time-Of-Day interrupts must be set again (for 

example, using SFC30 ACT_TINT in the startup program). 

Starting the Time-of-Day Interrupt 

To allow the CPU to start a Time-Of-Day interrupt, you must first set and then 

activate the Time-Of-Day interrupt. There are three ways of starting the interrupt: 

• Automatic start of the Time-Of-Day interrupt by assigning appropriate 

parameters with STEP 7 (parameter block "Time-Of-Day interrupts") 

• Setting and activating the Time-Of-Day interrupt with SFC28 SET_TINT and 

SFC30 ACT_TINT from within the user program 

• Setting the Time-Of-Day interrupt by assigning parameters with STEP 7 and 

activating the Time-Of-Day interrupt with SFC30 ACT_TINT in the user 

program. 


4-26 A5E00706944-01


Querying the Time-of-Day Interrupt 

To query which Time-Of-Day interrupts are set and when they are set to occur, you 

can do one of the following: 

• Call SFC31 QRY_TINT 

• Request the list "interrupt status" of the system status list. 

Deactivating the Time-of-Day Interrupt 

You can deactivate Time-Of-Day interrupts that have not yet been executed with 

SFC29 CAN_TINT. Deactivated Time-Of-Day interrupts can be set again using 

SFC28 SET_TINT and activated with SFC30 ACT_TINT. 

Priority of the Time-of-Day Interrupt OBs 

All eight Time-Of-Day interrupt OBs have the same priority class (2) as default and 

are therefore processed in the order in which their start event occurs. You can, 

however, change the priority class by selecting suitable parameters. 

Changing the Set Time 

You can change the Time-Of-Day set for the interrupt as follows: 

• A clock master synchronizes the time for masters and slaves. 

• SFC0 SET_CLK can be called in the user program to set a new time. 

Reaction to Changing the Time 

The following table shows how Time-Of-Day interrupts react after the time has 

been changed. 

If... 

you move the time ahead and one or more 

Time-Of-Day interrupts were skipped, 

you have not deactivated the skipped Time-Of-Day 

interrupts in OB80, 

you have not deactivated the skipped Time-Of-Day 

interrupts in OB80, 

you move the time back, the start events for the 

Time-Of-Day interrupts occur again, 

Then... 

OB80 is started and the Time-Of-Day interrupts that 

were skipped are entered in the start information of 

OB80. 

the skipped Time-Of-Day interrupts are no longer 

executed. 

the first skipped Time-Of-Day interrupt is executed, 

the other skipped Time-Of-Day interrupts are 

ignored. 

the execution of the Time-Of-Day interrupt is 

repeated with S7-300-CPUs 

and not 

repeated for S7-400-CPUs and CPU 318. 


A5E00706944-01 4-27


4.2.4.2 Time-Delay Interrupt Organization Blocks (OB20 to OB23) 

The S7 CPUs provide time delay OBs with which you can program the delayed 

execution of parts of your user program. 

Rules for Time-Delay Interrupts 

Time delay interrupts can only be executed when the corresponding organization 

block exists in the CPU program. If this is not the case, an error message is 

entered in the diagnostic buffer and asynchronous error handling is executed 

(OB80, see Error Handling Organization Blocks (OB70 to OB87 / OB121 to 

OB122)). 

Time delay interrupt OBs that were deselected by the parameter assignment 


STOP mode. 

Time delay interrupts are triggered when the delay time specified in SFC32 

SRT_DINT has expired. 

Starting the Time-Delay Interrupt 

To start a time delay interrupt, you must specify the delay time in SFC32 after 

which the corresponding time delay interrupt OB is called. Refer to the "S7-300 

Programmable Controller, Hardware and Installation Manual" and "S7-400, M7-400 

Programmable Controllers Module Specifications Reference Manual" for the 

maximum permitted length of the delay time. 

Priority of the Time-Delay Interrupt OBs 

The default priority for the time-delay interrupt OBs is priority class 3 to 6. You can 

assign parameters to change the priority classes. 


4-28 A5E00706944-01


4.2.4.3 Cyclic Interrupt Organization Blocks (OB30 to OB38) 

The S7 CPUs provide cyclic interrupt OBs that interrupt cyclic program processing 

at certain intervals. 

Cyclic interrupts are triggered at intervals. The time at which the interval starts is 

the mode transition from STOP to RUN. 

Rules for Cyclic Interrupts 

When you specify the intervals, make sure that there is enough time between the 

start events of the individual cyclic interrupts for processing the cyclic interrupts 

themselves. 

If you assign parameters to deselect cyclic interrupt OBs, they can no longer be 

started. The CPU recognizes a programming error and changes to STOP mode. 

Starting the Cyclic Interrupt 

To start a cyclic interrupt, you must specify the interval in the cyclic interrupts 

parameter block using STEP 7. The interval is always a whole multiple of the basic 

clock rate of 1 ms. 

Interval = n X basic clock rate 1 ms 

Each of the nine available cyclic interrupt OBs has a default interval (see the 

following table). The default interval becomes effective when the cyclic interrupt OB 

assigned to it is loaded. You can, however, assign parameters to change the 

default values. Refer to your "S7-300 Programmable Controller, Hardware and 

Installation Manual" and your "S7-400, M7-400 Programmable Controllers Module 

Specifications Reference Manual" for the upper limit. 


A5E00706944-01 4-29


Phase Offset in Cyclic Interrupts 

To avoid cyclic interrupts of different cyclic interrupt OBs being started at the same 

point and possibly causing a time error (cycle time exceeded) you can specify a 

phase offset. The phase offset ensures that the execution of a cyclic interrupt is 

delayed by a certain time after the interval has expired. 

Phase offset = m X basic clock rate (where 0 ≤ m < n) 

The following figure shows how a cyclic interrupt OB with phase offset (OB37) is 

executed in contrast to a cyclic interrupt without phase offset (OB38). 

 

 

 

 

 

 

 

Priority of the Cyclic Interrupt OBs 

The following table shows the default intervals and priority classes of the cyclic 

interrupt OBs. You can assign parameters to change the interval and the priority 

class. 

Cyclic Interrupt OB Interval in ms Priority Class 

OB30 5000 7 

OB31 2000 8 

OB32 1000 9 

OB33 500 10 

OB34 200 11 

OB35 100 12 

OB36 50 13 

OB37 20 14 

OB38 10 15 


4-30 A5E00706944-01


4.2.4.4 Hardware Interrupt Organization Blocks (OB40 to OB47) 

The S7 CPUs provide hardware interrupt OBs that react to signals from the 

modules (for example, signal modules (SMs), communications processors (CPs), 

function modules (FMs)). With STEP 7, you can decide which signal from a 

configurable digital or analog module starts the OB. With CPs and FMs, use the 

appropriate parameter assignment dialogs. 

Hardware interrupts are triggered when a signal module with hardware interrupt 

capability and with an enabled hardware interrupt passes on a received process 

signal to the CPU or when a function module of the CPU signals an interrupt. 

Rules for Hardware Interrupts 

Hardware interrupts can only be executed when the corresponding organization 

block exists in the CPU program. If this is not the case, an error message is 

entered in the diagnostic buffer and asynchronous error handling is executed 

(OB80, see Error Handling Organization Blocks (OB70 to OB87 / OB121 to 

OB122)). 

If you have deselected hardware interrupt OBs in the parameter assignment, these 


STOP mode. 

Assigning Parameters to Signal Modules with Hardware Interrupt Capability 

Each channel of a signal module with hardware interrupt capability can trigger a 

hardware interrupt. For this reason, you must specify the following in the parameter 

sets of signal modules with hardware interrupt capability using STEP 7: 

• What will trigger a hardware interrupt. 

• Which hardware interrupt OB will be executed (the default for executing all 

hardware interrupts is OB40). 

Using STEP 7, you activate the generation of hardware interrupts on the function 

blocks. You assign the remaining parameters in the parameter assignment dialogs 

of these function modules. 

Priority of the Hardware Interrupt OBs 

The default priority for the hardware interrupt OBs is priority class 16 to 23. You 

can assign parameters to change the priority classes. 


A5E00706944-01 4-31


4.2.4.5 Startup Organization Blocks (OB100 / OB101 / OB102) 

Startup Types 

There are three distinct types of startup: 

• Hot restart (not in S7-300 and S7-400H) 

• Restart (warm restart) 

• Cold restart 

The following table shows which OB the operating system calls in each startup 

type. 

Startup Type 

Hot restart 

Restart (warm restart) 

Cold restart 

Related OB 

OB101 

OB100 

OB102 

Start Events for Startup OBs 

The CPU executes a startup after the following events: 

• After power up 

• After you switch the mode selector from STOP to RUN/RUN-P 

• After a request from a communication function 

• After synchronizing in multicomputing mode 

• In an H system after link-up (only on the standby CPU) 

Depending on the start event, the CPU used, and its set parameters the relevant 

startup OB (OB100, OB101, or OB102) is called. 

Startup Program 

You can specify the conditions for starting up your CPU (initialization values for 

RUN, startup values for I/O modules) by writing your program for the startup in the 

organization blocks OB100 for restart (warm restart), OB101 for hot restart, or 

OB102 for cold restart. 

There are no restrictions to the length of the startup program and no time limit 

since the cycle monitoring is not active. Time-driven or interrupt-driven execution is 

not possible in the startup program. During the startup, all digital outputs have the 

signal state 0. 


4-32 A5E00706944-01


Startup Type After Manual Restart 

On S7-300 CPUs only a manual restart (warm restart) or cold restart (CPU 318-2 

only) is possible. 

On some S7-400 CPUs, you can restart manually using the mode selector and the 

startup type switch (CRST/WRST) if this is permitted by the parameter assignment 

you made with STEP 7. A manual restart (warm restart) is possible without 

specifically assigning parameters. 

Startup Type After Automatic Restart 

On S7-300 CPUs, only a restart (warm restart) is possible following power up. 

On S7-400 CPUs, you can specify whether an automatic startup following power 

up leads to a restart (warm restart) or a hot restart. 

Clearing the Process Image 

When an S7-400 CPU is restarted, the remaining cycle is executed, and as default, 

the process image output table is cleared. You can prevent the process image 

being cleared if you want the user program to continue with the old values following 

a restart. 

Module Exists/Type Monitoring 

In the parameters, you can decide whether the modules in the configuration table 

are checked to make sure they exist and that the module type matches before the 

startup. 

If the module check is activated, the CPU will not start up if a discrepancy is found 

between the configuration table and the actual configuration. 

Monitoring Times 

To make sure that the programmable controller starts up without errors, you can 

select the following monitoring times: 

• The maximum permitted time for transferring parameters to the modules 

• The maximum permitted time for the modules to signal that they are ready for 

operation after power up 

• On S7-400 CPUs, the maximum time of an interruption during which a hot 

restart is permitted. 

Once the monitoring times expire, the CPU either changes to STOP, or only a 

restart (warm restart) is possible. 


A5E00706944-01 4-33


4.2.4.6 Background Organization Block (OB90) 

If you have specified a minimum scan cycle time with STEP 7 and this is longer 

than the actual scan cycle time, the CPU still has processing time available at the 

end of the cyclic program. This time is used to execute the background OB. If 

OB90 does not exist on your CPU, the CPU waits until the specified minimum scan 

cycle time has elapsed. You can therefore use OB90 to allow processes where 

time is not critical to run and thus avoid wait times. 

Priority of the Background OB 

The background OB has priority class 29, which corresponds to priority 0.29. It is 

therefore the OB with the lowest priority. Its priority class cannot be changed by 

reassigning parameters. 

The following figure shows an example of processing the background cycle, the 

main program cycle, and OB10 (in CPUs as of 10/98). 


4-34 A5E00706944-01


Programming OB90 

The run time of OB90 is not monitored by the CPU operating system so that you 

can program loops of any length in OB90. Ensure that the data you use in the 

background program are consistent by observing the following when programming: 

• The reset events of OB90 (see the "System Software for S7-300 and S7-400, 

System and Standard Functions" Reference Manual) 

• The process image update asynchronous to OB90. 


A5E00706944-01 4-35


4.2.4.7 Error Handling Organization Blocks (OB70 to OB87 / OB121 to 

OB122) 

Types of Errors 

The errors that can be detected by the S7 CPUs and to which you can react with 

the help of organization blocks can be divided into two basic categories: 

• Synchronous errors: these errors can be assigned to a specific part of the user 

program. The error occurs during the execution of a particular instruction. If the 

corresponding synchronous error OB is not loaded, the CPU changes to STOP 

mode when the error occurs. 

• Asynchronous errors: these errors cannot be directly assigned to the user 

program being executed. These are priority class errors, faults on the 

programmable logic controller (for example, a defective module), or redundancy 

errors. If the corresponding asynchronous error OB is not loaded, the CPU 

changes to STOP mode when the error occurs (exceptions: OB70, OB72, 

OB81, OB 87). 

The following table shows the types of errors that can occur, divided up into the 

categories of the error OBs. 

Asynchronous Errors/Redundancy 

Errors 

OB70 I/O Redundancy Error (only H CPUs) 

OB72 CPU Redundancy Error (only in H 

CPUs, for example, failure of a CPU) 

OB80 Time Error (for example, scan cycle 

time exceeded) 

OB81 Power Supply Error (for example, 

battery failure) 

OB82 Diagnostic Interrupt (for example, 

short circuit in the input module) 

OB83 Remove/Insert Interrupt (for example, 

removing an input module) 

OB84 CPU Hardware Fault (fault at the 

interface to the MPI network) 

OB85 Priority Class Error (for example, OB 

is not loaded) 

OB86 Rack Failure 

OB87 Communication Error (for example, 

incorrect message frame ID for global data 

communication) 

Synchronous Errors 

OB121 Programming Error (for example, DB 

is not loaded) 

OB122 I/O Access Error (for example, 

access to a signal module that does not 

exist) 


4-36 A5E00706944-01


Using OBs for Synchronous Errors 

Synchronous errors occur during the execution of a particular instruction. When 

these errors occur, the operating system makes an entry in the I stack and starts 

the OB for synchronous errors. 

The error OBs called as a result of synchronous errors are executed as part of the 

program in the same priority class as the block that was being executed when the 

error was detected. The details about the error that triggered the OB call are in the 

start information for the OB. You can use this information to react to the error 

condition and then to return to processing your program (for example, if an access 

error occurs on an analog input module, you can specify a substitute value in 

OB122 using SFC44 RPL_VAL). The local data of the error OBs, do, however, take 

up additional space in the L stack of this priority class. 

With S7-400 CPUs, one synchronous error OB can start a further synchronous 

error OB. This is not possible with S7-300 CPUs. 

Using OBs for Asynchronous Errors 

If the operating system of the CPU detects an asynchronous error, it starts the 

corresponding error OB (OB70 to OB73 and OB80 to OB87). The OBs for 

asynchronous errors have the highest priority as default and they cannot be 

interrupted by other OBs if all asynchronous error OBs have the same priority. If 

more than one asynchronous error OB with the same priority occurs 

simultaneously, they are processed in the order they occurred. 

Masking Start Events 

Using system functions (SFCs), you can mask, delay, or disable the start events for 

several OBs. For more detailed information about these SFCs and the organization 

blocks, refer to the "System Software for S7-300 and S7-400, System and 

Standard Functions" Reference Manual. 

Type of Error OB SFC Function of the SFC 

Synchronous error OBs 

Asynchronous error 

OBs 

SFC36 MSK_FLT 

SFC37 DMSK_FLT 

SFC39 DIS_IRT 

SFC40 EN_IRT 

SFC41 DIS_AIRT 

SFC42 EN_AIRT 

Masks individual synchronous errors. Masked errors 

do not start an error OB and do not trigger 

programmed reactions 

Unmasks synchronous errors 

Disables all interrupts and asynchronous errors. 

Disabled errors do not start an error OB in any of the 

subsequent CPU cycles and do not trigger 

programmed reactions 

Enables interrupts and asynchronous errors 

Delays higher priority interrupts and asynchronous 

errors until the end of the OB 

Enables higher priority interrupts and asynchronous 

errors 

Note 

If you want interrupts to be ignored, it is more effective to disable them using an 

SFC, rather than to download an empty OB (with the contents BE). 


A5E00706944-01 4-37



4-38 A5E00706944-01

5 Startup and Operation 

5.1 Starting STEP 7 

When you start Windows, you will find an icon for the SIMATIC Manager, the 

starting point for the STEP 7 software on the Windows interface. 

The quickest method to start STEP 7 is to position the cursor on the icon and 

double-click. The window containing the SIMATIC Manager is then opened. From 

here you can access all the functions you have installed for the standard package 

and any optional packages. 

Alternatively you can also start the SIMATIC Manager via the "Start" button in the 

taskbar of the operating system. You will find the entry under "Simatic". 

Note 

You will find more information about standard Windows operation and options in 

your Windows user's guide or in the online help of your Windows operating system. 


The SIMATIC Manager is the basic application for configuring and programming. 

You can perform the following functions in the SIMATIC Manager: 

• Set up projects 

• Configure and assign parameters to hardware 

• Configure hardware networks 

• Program blocks 

• Debug and commission your programs 

Access to the various functions is designed to be object-oriented, and intuitive and 

easy to learn. 

You can work with the SIMATIC Manager in one of two ways: 

• Offline, without a programmable controller connected 

• Online, with a programmable controller connected 

Note the relevant safety notices in each case. 


A5E00706944-01 5-1

Startup and Operation 

How to Proceed from Here 

You create automation tasks in the form of "Projects." You will make it easier for 

yourself if you read up on the following basic topics before you start work: 

• User interface 

• Some basic operating steps 

• Online help 


5-2 A5E00706944-01


5.2 Starting STEP 7 with Default Start Parameters 

From STEP 7 V5.0 onwards, you can create several symbols in the 

SIMATIC Manager and specify start parameters in the call line. By doing this, you 

can cause the SIMATIC Manager to position on the object described by these 

parameters. This allows you to jump to the corresponding locations in a project 

immediately just by double-clicking. 

On calling s7tgtopx.exe, you can specify the following start parameters: 

/e 

/o 

/h 

/onl 

The start parameter /onl causes the project to be opened online and the specified 

path to be called. 

/off 

The start parameter /off causes the project to be opened offline and the specified 

path to be called. 

/keep 

The start parameter /keep causes the following to occur: 

If the SIMATIC Manager is open, the already displayed projects are opened in 

addition to the new project to be explicitly opened by means of the command line. If 

the SIMATIC Manager is not yet open, then the new project is opened along with 

the projects stored in the session memory of the SIMATIC Manager. If this start 

parameter is not specified, the opened projects are closed first, the session 

memory is ignored and only the one specified project is opened. 

The easiest way to establish suitable parameters is described below. 

Establishing Parameters by Copying and Pasting 

Proceed as follows: 

1. On your desktop, create a new link to the file s7tgtopx.exe. This file is located 

in the installation directory under S7bin. 

2. Display the properties dialog box. 

3. Select the "Link" tab. The entry under "Target" should now be expanded as 

follows. 

4. Select the required object in the SIMATIC Manager. 

5. Copy the object to the clipboard using the key combination CTRL+ALT+C. 

6. Position the cursor at the end of the "Target" entry in the "Link" tab. 

7. Paste the contents of the clipboard using the key combination CTRL+V. 

8. Close the dialog box by confirming with "OK." 


A5E00706944-01 5-3


Example of Parameters: 

/e F:\SIEMENS\STEP7\S7proj\MyConfig\MyConfig.s7p /keep 

/o "1,8:MyConfig\SIMATIC 400(1)\CPU416-1\S7-Program(1)\Blocks\FB1" 

/h T00112001;129;T00116001;1;T00116101;16e /keep 

Note on the Structure of the Project Path 

The project path is the physical path in the file system. 

The complete logical path has the following structure: 

[View ID,online ID]:project name\{object name\}*\ object name 

Example: /o 1.8:MyConfig\SIMATIC 400(1)\CPU416-1\S7-Program(1)\Blocks\FB1 

Note on the Structure of the Logical Path 

The complete logical path and the Object ID can only be created using the copy 

and paste functions. 

However, it is also possible to specify the path which can be read by the user. In 

the example above, that would be: 

/o "MyConfig\SIMATIC 400(1)\CPU416-1\S7-Program(1)\Blocks\FB1". By adding 

/onl or /off the user can specify whether the path is valid in the online or offline 

window. You do not need to specify this if you use the copy and paste functions. 

Important: If the path contains blanks, it must be placed within quotation marks. 


5-4 A5E00706944-01


5.3 Calling the Help Functions 

Online Help 

The online help system provides you with information at the point where you can 

use it most efficiently. You can use the online help to access information quickly 

and directly without having to search through manuals. You will find the following 

types of information in the online help: 

• Contents: offers a number of different ways of displaying help information 

• Context-sensitive Help (F1 key): with the F1 key you access information on 

the object you just selected with the mouse or on the active dialog box or 

window 

• Introduction: gives a brief introduction to the use, the main features, and the 

functional scope of an application 

• Getting Started: summarizes the basic steps you need to execute to get 

started with the application 

• Using Help: provides a description of ways of finding specific information in the 

online help 

• About: provides information on the current version of the application 

Via the Help menu you can also access topics which relate to the current dialog 

situation from every window. 

Calling the Online Help 

You can call the online help in one of the following ways: 

• Select a menu command in the Help menu in the menu bar. 

• Click the "Help" button in a dialog box. You are then shown help on this dialog 

box. 

• Position the cursor in a window or dialog box on the topic you need help with 

and press the F1 key or select the menu command Help > Context-sensitive 

Help. 

• Use the question mark cursor in Windows. 

The last three of these ways of accessing the online help are known as 

context-sensitive help. 

Calling the Quick Help 

A quick help on buttons in the toolbar is displayed when you position the cursor on 

a button and leave it there for a moment. 


A5E00706944-01 5-5


5.4 Objects and Object Hierarchy 

In the same way that the Windows Explorer shows the directory structure of folders 

and files, the object hierarchy for projects and libraries in STEP 7 is shown in the 


The following figure shows an example of an object hierarchy. 

• Project Object 

• Station Object 

• Programmable Module Object 

• S7/M7 Program Object 

• Source File Folder Object 

• Block Folder Object 

Objects have the following functions: 

• Carriers of object properties, 

• Folders, 

• Carriers of functions (for example, to start a particular application). 

Objects as Carriers of Properties 

Objects can carry both functions and properties (such as settings). When you 

select an object, you can perform one of the following functions with it: 

• Edit the object using the menu command Edit > Open Object. 

• Open a dialog box using the menu command Edit > Object Properties and set 

object-specific options. 

A folder can also be a carrier of properties. 

Objects as Folders 

A folder (directory) can contain other folders or objects. These are displayed when 

you open the folder. 


5-6 A5E00706944-01


Objects as Carriers of Functions 

When you open an object, a window is displayed in which you can edit the object. 

An object is either a folder or a carrier of functions. An exception to this is stations: 

they are both folders (for programmable modules) and carriers of functions (used to 

configure the hardware). 

• If you double-click a station, the objects contained in it are displayed: the 

programmable modules and the station configuration (station as a folder). 

• If you open a station with the menu command Edit > Open Object, you can 

configure this station and assign parameters to it (station as the carrier of a 

function). The menu command has the same effect as a double-click on the 

"Hardware" object. 


A5E00706944-01 5-7


5.4.1 Project Object 

The project represents the entirety of all the data and programs in an automation 

solution, and is located at the top of an object hierarchy. 

Position in the Project View 







Symbol Object Folder Selection of Important Functions 

Project • Creating a Project 

• Archiving Projects and Libraries 

• Managing Multilingual Texts 

• Checking Projects for Optional Packages Used 

• Printing Project Documentation 

• Rearranging 

• Translating and Editing Operator Related Texts 

• Inserting Operator Station Objects 

• More than One User Editing Projects 

• Converting Version 1 Projects 

• Converting Version 2 Projects 

• Setting the PG/PC Interface 


5-8 A5E00706944-01


Symbol 

Objects in the 

Project Level 

Station: 

SIMATIC 300 station 

SIMATIC 400 station 

S7 program 

M7 program 

Network for starting 

the tool for network 

configuration and 

setting the network 

properties. 

Selection of Important Objects 

• Inserting Stations 

• Stations are both objects (project level) and 

object folder (station level). Other functions can 

be found under Station Object 

• S7/M7 Program without a Station or CPU 

• S7/M7 programs are both objects (project level) 

and object folders (program level). Other 

functions can be found under S7/M7 Program 

Object 

• Properties of Subnets and Communication 

Nodes 

• Overview: Global Data Communication 

• Procedure for Configuring Global Data 

Communication 

5.4.2 Library Object 

A library can contain S7/M7 programs and is used to store blocks. A library is 

located at the top of an object hierarchy. 

• Library Object 





Library • Overview of the Standard Libraries 

• Working with Libraries 

• Archiving Projects and Libraries 

Symbol 


Library Level 

S7 program 

M7 program 

Selection of Important Functions 

• Inserting an S7/M7 Program 

• S7/M7 programs are both objects (project level) 

and object folders (program level). Other 

functions can be found under S7/M7 Program 

Object 


A5E00706944-01 5-9


5.4.3 Station Object 

A SIMATIC 300/400 station represents a S7 hardware configuration with one or 

more programmable modules. 









Station • Inserting a Station 

• Uploading a Station 

• Downloading a Configuration to a Programmable 

Controller 

• Uploading a Configuration from a Station 

• Displaying CPU Messages and User-Defined 

Diagnostic Messages 

• Configuring the 'Reporting of System Errors' 

• Diagnosing Hardware and Displaying Module 

Information 

• Displaying and Changing the Operating Mode 

• Displaying and Setting the Time and Date 

• Erasing the Load/Work Memory and Resetting the 

CPU 

SIMATIC PC Station 

(Not assigned) 

• Creating and Assigning Parameters to SIMATIC PC 

Stations 

• Configuring Connections for a SIMATIC PC Station 

• Uploading a SIMATIC PC Station 

SIMATIC PC Station 

(Assigned) 

• Highlighting the SIMATIC PC Station to be 

Configured in the Network View 


5-10 A5E00706944-01


Symbol 

Objects in the Selection of Important Functions 

Station Level 

Hardware • Basic Procedure for Configuring Hardware 

• Basic Steps for Configuring a Station 

• Overview: Procedure for Configuring and Assigning 

Parameters to a Local Configuration 

• Basic Procedure for Configuring a DP Master 

System 

• Configuring Multicomputing Operation 

Programmable 

module 

• Programmable modules are both objects (station 

level) and object folders ("Programmable Modules" 

level). Other functions can be found under 

Programmable Module Object 


A5E00706944-01 5-11


5.4.4 Programmable Module Object 

A programmable module represents the parameter assignment data of a 

programmable module (CPUxxx, FMxxx, CPxxx). The system data of modules with 

no retentive memory (for example, CP441) are loaded via the CPU of the station. 

For this reason, no "system data" object is assigned to such modules and they are 

not displayed in the project hierarchy. 









Programmable 

module 

Object representing a 

programmable 

module 

• Overview: Procedure for Configuring and Assigning 

Parameters to a Local Configuration 



• Configuring 'Reporting of System Errors' 

• Diagnosing Hardware and Displaying Module 

Information 

• Downloading via EPROM Memory Cards 

• Password Protection for Access to Programmable 

Controllers 

• Displaying the Force Values Window 

• Displaying and Changing the Operating Mode 

• Displaying and Setting the Time and Date 

• Setting the Operating Behavior 

• Erasing the Load/Work Memory and Resetting the 

CPU 

• Diagnostics Symbols in the Online View 

• Division of the Memory Areas 

• Saving Downloaded Blocks on Integrated EPROM 

• Updating the Operating System on the 

Programmable Logic Controller 

• Displaying Modules Configured with Later STEP 7 

Versions 


5-12 A5E00706944-01


Symbol 


"Programmable 

Modules" level 

Programs: 

S7 program 

M7 program 


• Inserting an S7/M7 Program 

• S7/M7 programs are both objects (project level) and 

object folders (program level). Other functions can 

be found under S7/M7 Program Object 

Program 

Connections for 

defining connections 

within the network 

• Networking Stations within a Project 

• Connection Types and Connection Partners 

• What You Should Know About the Different 

Connection Types 

• Entering a New Connection 

• Configuring Connections for Modules in a SIMATIC 

Station 


A5E00706944-01 5-13


5.4.5 S7/M7 Program Object 

A (S7/M7) program folder contains software for S7/M7 CPU modules or software 

for non-CPU modules (for example, programmable CP or FM modules). 









S7 Program • Inserting an S7-/M7-Program 

• Setting the Address Priority 

• Basic Procedure for Creating Logic Blocks 

• Assigning Message Numbers 

• How to Assign and Edit User-Specific Diagnostics 

Messages (Project-Oriented) 

• How to Assign and Edit User-Specific Diagnostics 

Messages (CPU-Oriented) 


• Managing Multilingual Texts 



• Program Measures for Handling Errors 

M7 program • Procedure for M7 Systems 

Program • Creating the Software in the Project (General) 


5-14 A5E00706944-01


Symbol 

Objects in the Selection of Important Functions 

Program Level 

Source file folder • Other functions can be found under Source File 

Folder Object 

Block folder • Other functions can be found under Block Folder 

Object 

Text libraries folder • User Text Libraries 

Symbol table for 

assigning symbols to 

signals and other 

variables 

• Absolute and Symbolic Addressing 

• Structure and Components of the Symbol Table 

• Entering Shared Symbols 

• General Tips on Entering Symbols 

• How to Assign and Edit Symbol-Related Messages 

(Project-Oriented) 

• How to Assign and Edit Symbol-Related Messages ( 

CPU-Oriented) 


• Configuring Operator Control and Monitoring 

Attributes via the Symbol Table 

• Editing the Communication Attribute 

• Exporting and Importing Symbol Tables 


A5E00706944-01 5-15


5.4.6 Block Folder Object 

A block folder of an offline view can contain: logic blocks (OB, FB, FC, SFB, SFC), 

data blocks (DB), user-defined data types (UDT) and variable tables. The system 

data object represents system data blocks. 

The block folder of an online view contains the executable program parts that have 

been downloaded to the programmable controller. 








Symbol 

Object Selection of Important Functions 

Folder 

Blocks • Downloading with Project Management 

• Downloading without Project Management 

• Overview of the Available Reference Data 

• Rewiring 

• Comparing Blocks 


• Jumps to Language Descriptions and Help on Blocks, System Attributes 

Symbol 

Objects in 

the Block 

Folder 

Blocks in 

general 

Organization 

Block (OB) 


• Basic Procedure for Creating Logic Blocks 

• Creating Blocks 

• Basic Information on Programming in STL Source Files 

• Comparing Blocks 

Additional Functions: 

• Introduction to Data Types and Parameter Types 

• Requirements for Downloading 

• Testing using Program Status 

• What You Should Know About Testing in Single-Step Mode/Breakpoints 

• Rewiring 

• Help on Blocks 


5-16 A5E00706944-01


Symbol 

Objects in 

the Block 

Folder 

Function 

(FC) 

Function 

Block (FB) 





• Testing using Program Status 

• What You Should Know About Testing in Single-Step Mode/Breakpoints 

• Rewiring 

• Attributes for Blocks and Parameters 



• Using Multiple Instances 


• Testing Using Program Status 

• What You Should Know about Testing in Single-Step Mode/Breakpoints 

• Rewiring 


• How to Assign and Edit Block-Related Messages (Project-Oriented) 

• How to Create Block-Related Messages (CPU-Oriented) 

• How to Configure PCS 7 Messages (Project-Oriented) 

• How to Configure PCS 7 Messages (CPU-Oriented) 


• Assigning Monitor/Control Attributes to Function Block Parameters 

User-Defined 

Data Type 

(UDT) 

DB (Global 

Data Blocks) 

System 

Function 

(SFC) 

• Creating Blocks 

• Basic Information on Programming in STL Source Files 


• Using User-Defined Data Types to Access Data 


• Data View of Data Blocks 

• Declaration View of Data Blocks 


• Program Status of Data Blocks 


• Using Multiple Instances 



(Instance DBs Only) 

• How to Assign and Edit Block-Related Messages (CPU-Oriented) 

(Instance DBs Only) 

• How to Configure PCS7 Messages (Project-Oriented) (Instance DBs Only) 

• How to Configure PCS7 Messages (CPU-Oriented) (Instance DBs Only) 

• Translating and Editing Operator Related Texts (Instance Data Blocks 

Only) 





A5E00706944-01 5-17


Symbol 

Objects in 

the Block 

Folder 

SFB (System 

Function 

Blocks) 





• How to Create Block-Related Messages (CPU-Oriented) 

• How to Configure PCS7 Messages (Project-Oriented) 

• How to Configure PCS7 Messages (CPU-Oriented) 



Block with 

KNOW HOW 

protection 

• Rules for Defining Block Properties in STL Sources 

• Block Properties 

{bmc 

Manager 

_Bst_Va 

r.bmp 

Diagnosticcapable 

block 

Block was 

created with 

the F-FBD/- 

LAD/-STL/- 

DB 

programming 

language 

Variable 

Table (VAT) 

System Data 

Block 

(SDB) 

Additional information is available in the documentation for the S7-PDIAG 

optional package. 

Additional information is available in the documentation for the S7 Distributed 

Safety optional package. 

• Basic Procedure when Monitoring and Modifying with the Variable Table 

• Introduction to Testing with the Variable Table 

• Introduction to Monitoring Variables 

• Introduction to Modifying Variables 

• Introduction to Forcing Variables 

System data blocks (SDBs) are only edited indirectly via functions: 

• Introduction to Configuring Hardware 

• Properties of Subnets and Communication Nodes 

• Overview: Global Data Communication 

• Assigning and Editing Symbol-Related Messages 



5-18 A5E00706944-01


5.4.7 Source File Folder Object 

A source file folder contains source programs in text format. 









Source File Folder • Basic Information on Programming in STL Source 

Files 

• Exporting Source Files 

• Importing Source Files 

Symbol 

Objects in Source 

File Folder 

Source file 

(for example, STL 

source file) 


• Basic Information on Programming in STL Source 

Files 

• Creating STL Source Files 

• Inserting Block Templates in STL Source Files 

• Inserting Source Code from Existing Blocks in STL 

Source Files 

• Checking Consistency in STL Source Files 

• Compiling STL Source Files 

• Generating STL Source Files from Blocks 

• Exporting Source Files 

• Importing Source Files 

Network template • Working with Network Templates 


A5E00706944-01 5-19


5.4.8 S7/M7 Program without a Station or CPU 

You can create programs without having configured a SIMATIC station beforehand. 

This means that you can initially work independently of the module and module 

settings you intend to program. 

Creating an S7/M7 Program 

1. Open the relevant project using the menu command File > Open or activate 

the project window. 

2. Select the project in the project window of the offline view. 

3. Select one of the following menu commands, depending on which 

programmable controller the program is being created for: 

Insert > Program > S7 Program, if your program is to run on a SIMATIC S7 

device. 

Insert > Program > M7 Program, if your program is to run on a SIMATIC M7 

device. 

The S7/M7 program is added and arranged directly below the project in the project 

window. It contains a folder for the blocks and an empty symbol table. You can now 

create and program blocks. 

Assigning a Program to a Programmable Module 

When you insert programs that are not dependent on a particular module, you can 

easily assign them to a module later on by copying or moving these programs to 

the module symbol using the drag and drop function. 

Adding a Program to a Library 

If the program is to be used for a SIMATIC S7 programmable controller and you 

want to use it many times as a "software pool," you can also insert it in a library. 

However, when testing, the programs must lie directly under a project, because this 

is the only way in which to establish a connection to the programmable controller. 

Accessing a Programmable Controller 

Select the online view of the project. You can make the address settings in the 

dialog box containing the program properties. 

Note 

When deleting stations or programmable modules, you will be asked if you also 

want to delete the program contained within. If you choose not to delete the 

program, it will be attached directly below the project as a program without a 

station. 


5-20 A5E00706944-01


5.5 User Interface and Operation 

5.5.1 Operating Philosophy 

The aim: Easy Operation 

It is the aim of the graphic user interface to provide maximum and intuitive 

operating comfort. You will therefore find objects you already know from your daily 

work, e.g. stations, modules, programs, blocks. 

Actions you perform under STEP 7 include the creation, selection and manipulation 

of such objects. 

Differences to Tool-Based Operation 

When starting work with conventional tools, the first thing you have to do is to 

choose the appropriate tool for a specific solution and then call this tool. 

The basic procedure of object-oriented operation is to select an object and then 

open it for editing. 

Object oriented operation does not require knowledge of a special instruction 

syntax. On the GUI, icons you can open via menu command or mouse click 

represent objects. 

When you open an object, the application automatically calls the appropriate 

software component for displaying or editing the content of the object. 

Continue ... 

Below we describe the basic actions for editing objects. Please pay proper 

attention to this topic, as all subsequent topics will be based on these basic 

operations. 


A5E00706944-01 5-21


5.5.2 Window Arrangement 

The standard components of a window are shown in the following figure: 

Title Bar and Menu Bar 

The title bar and menu bar are always found at the top of a window. The title bar 

contains the title of the window and icons for controlling the window. The menu bar 

contains all menus available in the window. 

Toolbar 

The toolbar contains icons (or tool buttons) which provide shortcuts to frequently 

used and currently available menu bar commands via a single mouse click. A brief 

description of the function of the respective button is displayed together with 

additional information in the status bar when you position the cursor briefly on the 

button. 

If access to a button is not possible in the current configuration, the button is 

grayed out. 

Status Bar 

The status bar displays context-specific information. 


5-22 A5E00706944-01


5.5.3 Elements in Dialog Boxes 

Making Entries in Dialog Boxes 

In dialog boxes you can enter information which is required for executing a 

particular task. The components which appear most frequently in dialog boxes are 

explained using the example in the following figure. 

List Boxes and Combination Boxes 

Text boxes sometimes have an arrow pointing downwards beside them. This arrow 

shows that there are more options available to choose from for this box. Click on 

the arrow to open a list box or combination box. If you click on an entry in the list, it 

is automatically displayed in the text box. 

Tabs in Dialog Boxes 

The content of some dialog boxes is organized using tabs to improve the clarity of 

the information by dividing the dialog box into tab cards (see figure below). 

The names of the tab cards are shown on tabs along the top edge of the dialog 

box. To bring a particular tab card to the foreground, you simply click on its tab. 


A5E00706944-01 5-23


5.5.4 Creating and Managing Objects 

Some basic processing steps are the same for all objects and do not depend on 

the object type. These standard handling sequences are summarized here. This 

knowledge of standard procedures is required to move on to other sections in the 

manual. 

The usual sequence of steps when handling objects is: 

• Create an object 

• Select an object 

• Perform actions with the object (for example, copy, delete). 

Setting the Path to Create New Projects/Libraries 

New user projects, libraries and multiprojects are stored in the default folder 

"\Siemens\Step7\S7proj". If you want to store them in another folder, you should 

set your custom path for these objects before you save projects, libraries and 

multiprojects for the first time. To do this, select the menu command Options > 

Customize. In the "General" tab of the dialog box displayed you can specify the 

path name under which you want to store new projects or libraries. 

Creating Objects 

The STEP 7 wizard "New Project" offers support with creating a new project and 

inserting objects. Use the menu command File > "New Project" Wizard to open 

the wizard. In the dialog boxes displayed you can set the structure of your project 

and then have the wizard create the project for you. 

If you do not wish to use the wizard, you can create projects and libraries using the 

menu command File > New. These objects form the starting point of an object 

hierarchy. You can create all other objects in the hierarchy using the commands in 

the Insert menu, provided they are not created automatically. The exception to this 

are the modules in a SIMATIC station which are created when you configure the 

hardware or by using the "New Project" wizard. 


5-24 A5E00706944-01


Opening Objects 

There are a number of ways to open an object in the detailed view: 

• Double-click on the object icon 

• Select the object and then the menu command Edit > Open Object. This only 

works for objects that are not folders. 

Once you have opened an object, you can create or change its contents. 

When you open an object that does not contain other objects, its contents are 

represented by a suitable software component in a new window for editing 

purposes. You cannot change objects whose contents are already being used 

elsewhere. 

Note 

Exception: Stations appear as folders for programmable modules (when you 

double-click them) and for the station configuration. If you double-click the 

"Hardware" object, the application for configuring hardware is started. Selecting the 

station and selecting the menu command Edit > Open Object has the same effect. 

Building an Object Hierarchy 

Use the "New Project" wizard to create the object hierarchy. When you open a 

folder, the objects it contains are displayed on the screen. You can now create 

more objects in the folder using the Insert menu, for example, additional stations in 

a project. Only the commands for those objects which can be inserted in the 

current folder are active in the Insert menu. 

Setting Object Properties 

Object properties are data belonging to the object which determine its behavior. 

The dialog box for setting object properties appears automatically when you create 

a new object and properties have to be set. The properties can also be changed at 

a later date. 

Using the menu command Edit > Object Properties, a dialog box is opened in 

which you can display or set the properties for the selected object. 

Using the menu command Edit > Special Object Properties, you can open dialog 

boxes and enter data required for operator control and monitoring functions and for 

configuring messages. 

For example, in order to display the special object properties of a block for operator 

control and monitoring, the block must be marked as being relevant for operator 

control and monitoring, meaning that the system attribute "s7_m_c" must be set to 

the value "true" in the "Attributes" tab of the block properties. 


A5E00706944-01 5-25


Note 

• Properties of the "System Data" folder and the "Hardware" object cannot be 

displayed or changed. 

• You cannot write in the dialog boxes for object properties of a read-only 

project. In this case, the input boxes are grayed out. 

• If you display the properties of programmable modules, you cannot edit the 

displayed parameters for reasons of consistency. To edit the parameters you 

must open the "Configuring Hardware" application. 

• If you change the settings for objects on the programming device (for example, 

the configuration data of a module), they are not yet effective in the target 

system, because the system data blocks in which the settings are saved have 

to be in the target system. 

• If you load an entire user program, the system data blocks are also 

automatically transferred. If you change the settings after having loaded the 

program, you can reload the "System data" object in order to transfer the 

settings to the target system. 

• It is strongly recommended to edit the folders exclusively with STEP 7, sind 

they can be physically structured in a different way than you see in the 


Cutting, Pasting, Copying 

Most objects can be cut, pasted, or copied as usual under Windows. The menu 

commands for these functions are found in the Edit menu. 

You can also copy objects by dragging and dropping. If you attempt to move or 

copy to an illegal destination, the cursor displays a prohibited sign as a warning. 

When you copy an object, the whole hierarchy beneath it is also copied. This 

enables components you create in an automation task to be used again and again. 

Note 

The connection table in the "Connections" folder cannot be copied. Note that when 

you copy lists of operator-relevant texts, only those languages installed in the 

destination object are accepted. 

You will find a step-by-step guide to copying under Copying Objects. 

Renaming Objects 

The SIMATIC Manager assigns standard names to some new objects. These 

names are generally formed from the type of object (if a number of objects of this 

type can be created in the same folder) and a number. 

For example, the first S7 program will be named "S7 Program(1)", the second "S7 

Program(2)" etc. The symbol table is simply called "Symbols" as it can only exist 

once in each folder. 

You can change the names of most objects and assign them names which are 

more relevant to their content. 

With projects, the directory names in the path must not have more than 8 

characters. Otherwise, there may be problems when archiving and using "C for 

M7" (Borland compiler). 


5-26 A5E00706944-01


You can change the name of an object directly or using the object properties. 

Directly: 

When you slowly click twice on the name of a selected object, a frame appears 

around the text. You can then edit the name using the keyboard. 

Using the menu: 

Select the required object in the project window and select the menu command 

Edit > Rename. A frame appears around the text. You can then edit the name 

using the keyboard. 

If you are not allowed to change the name: 

If you are not allowed to change the name of an object, the input field is shown in 

gray in the dialog box, the current name is displayed, and text entries are not 

possible. 

Note 

If you move the mouse pointer out of the name box while editing the name and 

execute another action (for example, select a menu command), the edit procedure 

is terminated. The changed name is accepted and entered if it is allowed. 

You will find a step-by-step guide to renaming under Renaming Objects. 

Moving Objects 

With the SIMATIC Manager you can move objects from one folder to another even 

if the destination is in another project. When you move a folder its contents are all 

moved as well. 

Note 

You cannot move the following objects: 

• Connections 

• System data blocks (SDB) in the online view 

• System functions (SFC) and system function blocks (SFB) in the online view 

You will find a step-by-step guide to moving under Moving Objects. 

Sorting Objects 

You can sort objects in the detailed view (menu command View > Details) 

according to their attributes. To do this, click on the corresponding header of the 

required attribute. When you click again, the sort order is reversed. Blocks of one 

type are sorted according to their numerical order, for example, FB1, FB2, FB11, 

FB12, FB21, FC1. 


A5E00706944-01 5-27


Default Sort Order 

When you re-open a project, the objects in the detailed view are displayed 

according to a default sort order. Examples: 

• Blocks are shown in the order "System data, OB, FB, FC, DB, UDT, VAT, SFB, 

SFC." 

• In a project, all stations are shown first and then the S7 programs. 

The default is not therefore an alphanumeric ascending or descending sort order in 

the detailed view. 

Restoring the Default Sort Order 

After resorting, for example, by clicking on the column header "Object Name," you 

can restore the default order if you proceed as follows: 

• Click the column header "Type" in the detailed view. 

• Close the project and open it again. 

Deleting Objects 

You can delete folders and objects. If you delete a folder, all the objects contained 

in it are also deleted. 

You cannot undo the delete procedure. If you are not sure whether you really no 

longer need an object, it is better to archive the whole project first. 

Note 

You cannot delete the following objects: 

• Connections 

• System data blocks (SDB) in the online view 

• System functions (SFC) and system function blocks (SFB) in the online view 

You will find a step-by-step guide to deleting under Deleting Objects. 


5-28 A5E00706944-01


5.5.5 Selecting Objects in a Dialog Box 

Selecting objects in a dialog box (browser) is an action which you will need 

regularly for a large number of different edit steps. 

Calling the Browser 

You call the browser dialog in the hardware configuration application, for example, 

using menu commands such as Station > New/Open (one exception is the basic 

application window "SIMATIC Manager"). 

Structure of a Browser Dialog 

In the browser you have the following selection options as shown in the following 

figure. 


A5E00706944-01 5-29


5.5.6 Session Memory 

The SIMATIC Manager can save the contents of windows (that is, the projects and 

libraries open), and the layout of the windows. 

• Using the menu command Options > Customize, you define whether the 

window contents and layout are to be saved at the end of a session. At the start 

of the next session, these window contents and layout are restored. In the open 

projects, the cursor is positioned on the last folder selected. 

• Using the menu command Window > Save Settings you save the current 

window contents and the window arrangement. 

• Using the menu command Window > Restore Settings you restore the window 

contents and layout that you saved with the menu command Window > Save 

Settings. In the open projects, the cursor is positioned on the last folder 

selected. 

Note 

The window contents of online projects, the contents of the "Accessible Nodes" 

window, and the contents of the "S7 Memory Card" window are not saved. 

Any passwords you may have entered for access to programmable controllers 

(S7-300/S7-400) are not saved at the end of a session. 


5-30 A5E00706944-01


5.5.7 Changing the Window Arrangement 

To cascade all the displayed windows one behind the other, select one of the 

following options: 

• Select the menu command Window > Arrange > Cascade. 

• Press the key combination SHIFT + F5. 

To arrange all the displayed windows from top to bottom on the screen, select the 

menu command Window > Arrange > Horizontally. 

To arrange all the displayed windows from left to right on the screen, select the 

menu command Window > Arrange > Vertically. 

5.5.8 Saving and Restoring the Window Arrangement 

The STEP 7 applications have a feature which enables you to save the current 

window arrangement and restore it at a later stage. You can make the setting using 

the menu command Options > Customize in the "General" tab. 

What Is Saved? 

When you save the window layout the following information is recorded: 

• Position of the main window 

• Opened projects and libraries and their respective window positions 

• Order of any cascaded windows 

Note 

The window content of online projects, the content of the "Accessible Nodes" 

window, and the content of the "S7 Memory Card" window are not saved. 

Saving the Window Layout 

To save the current window arrangement, select the menu command Window > 

Save Settings. 

Restoring the Window Layout 

To restore the saved window arrangement, select the menu command Window > 

Restore Settings. 

Note 

When you restore a window, only the part of the hierarchy containing the object that was 

selected when the window arrangement was saved is displayed in detail. 


A5E00706944-01 5-31


5.6 Keyboard Operation 

International Key Names 

HOME 

END 

PAGE UP 

PAGE DOWN 

CTRL 

ENTER 

DEL 

INSERT 

German Key Names 

POS1 

ENDE 

BILD AUF 

BILD AB 

STRG 

Eingabetaste 

ENTF 

EINFG 

5.6.1 Key Combinations for Menu Commands 

Every menu command can be selected by typing a key combination with the ALT 

key. 

Press the following keys in the order shown: 

• ALT key 

• The letter underlined in the menu name you require (for example, ALT, F for the 

menu "File" - if the menu "File" is included in the menu bar). The menu is 

opened. 

• The letter underlined in the menu command you require (for example, N for the 

menu command "New"). If the menu command has a submenu, the submenu is 

also opened. Proceed as above until you have selected the whole menu 

command by typing the relevant letters. 

Once you have entered the last letter in the key combination, the menu command 

is executed. 

Examples: 

Menu Command Key Combination 

File > Archive ALT, F, A 

Window > Arrange > Cascade ALT, W, A, C 


5-32 A5E00706944-01


Shortcuts for Menu Commands 

Command 

Shortcut 

New (File Menu) CTRL+N 

Open (File Menu) CTRL+O 

Save as ("File" Menu) CTRL+S 

Print > Object Table ("File" Menu) CTRL+P 

Print > Object Content ("File" Menu) CTRL+ALT+P 

Exit ("File" Menu) ALT+F4 

Cut ("Edit" Menu) CTRL+X 

Copy ("Edit" Menu) CTRL+C 

Paste ("Edit" Menu) CTRL+V 

Delete ("Edit" Menu) DEL 

Select All ("Edit" Menu) CTRL+A 

Rename ("Edit" Menu) F2 

Object Properties ("Edit" Menu) ALT+RETURN 

Open Object ("Edit" Menu) CTRL+ALT+O 

Compile ("Edit" Menu) CTRL+B 

Download (PLC Menu) CTRL+L 

Diagnostics/Setting 

CTRL+D 

> Module Status ("PLC" Menu) 

Diagnostics/Setting 

CTRL+I 

> Operating Mode ("PLC" Menu) 

Update ("View" Menu) F5 

Updates the status display of the visible CPUs in the CTRL+F5 

online view 

Customize ("Options" Menu) CTRL+ALT+E 

Reference Data > Show ("Options" Menu) CTRL+ALT+R 

Arrange > Cascade (Window Menu) SHIFT+F5 

Arrange > Horizontally (Window Menu) SHIFT+F2 

Arrange > Vertically (Window Menu) SHIFT+F3 

Context-Sensitive Help (Help Menu) F1 

(If there is a current context, for 

example, a selected menu 

command, the relevant help topic 

is opened. Otherwise the help 

contents page is displayed.) 


A5E00706944-01 5-33


5.6.2 Key Combinations for Moving the Cursor 

Moving the Cursor in the Menu Bar/Pop-Up Menus 

To 

move to the menu bar 

move to the pop-up menu 

move to the menu that contains the letter or 

number underlined which you typed in 

select the menu command whose 

underlined letter or number corresponds to 

the letter you have typed 

move one menu command to the left 

move one menu command to the right 

move one menu command up 

move one menu command down 

activate the selected menu command 

deselect the menu name or close the open 

menu and return to the text 

Press 

F10 

SHIFT+F10 

ALT+underlined character in a menu title 

Underlined character in the menu command 

LEFT ARROW 

RIGHT ARROW 

UP ARROW 

DOWN ARROW 

ENTER 

ESC 

Moving the Cursor When Editing Text 

To move 

one line up or one character to the left in a 

text consisting of only one line 

one line down or one character to the right 

in a text consisting of only one line 

one character to the right 

one character to the left 

one word to the right 

one word to the left 

to the beginning of the line 

to the end of the line 

to the previous screen 

to the next screen 

to the beginning of the text 

to the end of the text 

Press 

UP ARROW 

DOWN ARROW 

RIGHT ARROW 

LEFT ARROW 

CTRL+RIGHT ARROW 

CTRL+LEFT ARROW 

HOME 

END 

PAGE UP 

PAGE DOWN 

CTRL+HOME 

CTRL+END 


5-34 A5E00706944-01


Moving the Cursor When Editing Tables 

To move 

One row up 

One row down 

One character or cell to the left 

One character or cell to the right 

To the beginning of the row 

To the end of the row 

To the beginning of the cell 

To the end of the cell 

To the previous screen 

To the next screen 

To the beginning of the table 

To the end of the table 

In the symbol table only: to the "Symbol" 

column 

In the symbol table only: to the "Comment" 

column 

Press 

UP ARROW 

DOWN ARROW 

RIGHT ARROW 

LEFT ARROW 

CTRL+RIGHT ARROW 

CTRL+LEFT ARROW 

HOME 

END 

PAGE-UP 

PAGE-DOWN 

CTRL+HOME 

CTRL+END 

SHIFT+HOME 

SHIFT+END 

Moving the Cursor in Dialog Boxes 

To 

move from one input box to the next (from 

left to right and from top to bottom) 

move one input box in the reverse direction 

move to the input box or option that 

contains the letter or number underlined 

which you typed in 

select in a list of options 

open a list of options 

select or deselect an item in a list 

confirm the entries and close the dialog box 

("OK" button) 

close the dialog box without saving the 

changes ("Cancel" button) 

Press 

TAB 

SHIFT+TAB 

ALT+underlined character in a menu title 

an arrow key 

ALT+DOWN ARROW 

SPACEBAR 

ENTER 

ESC 


A5E00706944-01 5-35


5.6.3 Key Combinations for Selecting Text 

To select or deselect text 

one character at a time to the right 

one character to the left 

to the beginning of a comment line 

to the end of a comment line 

one row in a table 

one line of text up 

one line of text down 

to the previous screen 

to the next screen 

the text to the beginning of the file 

the text to the end of the file 

Press 

SHIFT+RIGHT ARROW 

SHIFT+LEFT ARROW 

SHIFT+HOME 

SHIFT+END 

SHIFT+SPACE 

SHIFT+UP ARROW 

SHIFT+DOWN ARROW 

SHIFT+PAGE UP 

SHIFT+PAGE DOWN 

CTRL+SHIFT+HOME 

CTRL+SHIFT+END 

5.6.4 Key Combinations for Access to Online Help 

To 

open the Help 

activate the question mark symbol for contextsensitive 

help 

close the Help window and return to the 

application 

Press 

F1 

(If there is a current context, for 

example, a selected menu command, 

the relevant help topic is opened. 

Otherwise the help contents page is 

displayed.) 

SHIFT+F1 

ALT+F4 


5-36 A5E00706944-01


5.6.5 Key Combinations for Toggling between Windows 

To 

toggle between the panes in a window 

return to the previous pane, if there is no 

dockable window 

toggle between the document window and a 

dockable window in the document (for example, 

variable declaration window). 

If there are no dockable windows, you can use 

this key combination to return to the previous 

pane. 

toggle between document windows 

return to the previous document window 

toggle between non-document windows 

(application framework and dockable windows 

in the application framework; 

when you return to the framework, this key 

combination activates the document window 

that was last active) 

return to the previous non-document window 

Press 

F6 

Shift+F6 

Shift+F6 

Ctrl+F6 

Shift+Ctrl+F6 

Alt+F6 

Shift+Alt+F6 

close the active window 

Ctrl+F4 


A5E00706944-01 5-37



5-38 A5E00706944-01

6 Setting Up and Editing the Project 

6.1 Project Structure 

Projects are used to store the data and programs which are created when you put 

together an automation solution. The data collected together in a project include: 

• Configuration data on the hardware structure and parameters for modules, 

• Configuration data for communication in networks, and 

• Programs for programmable modules. 

The main task when you create a project is preparing these data for programming. 

Data are stored in a project in object form. The objects in a project are arranged in 

a tree structure (project hierarchy). The display of the hierarchy in the project 

window is similar to that of the Windows Explorer. Only the object icons have a 

different appearance. 

The top end of the project hierarchy is structured as follows: 

1. 1st Level: Project 

2. 2nd Level: Subnets, stations, or S7/M7 programs 

3. 3rd Level: depends on the object in level 2. 

Project Window 

The project window is split into two halves. The left half shows the tree structure of 

the project. The right half shows the objects that are contained in the object open in 

the left half in the selected view (large symbols, small symbols, list, or details). 

Click in the left half of the window on the box containing a plus sign to display the 

full tree structure of the project. The resulting structure will look something like the 

following figure. 


A5E00706944-01 6-1

Setting Up and Editing the Project 

At the top of the object hierarchy is the object "S7_Pro1" as the icon for the whole 

project. It can be used to display the project properties and serves as a folder for 

networks (for configuring networks), stations (for configuring the hardware), and for 

S7 or M7 programs (for creating software). The objects in the project are displayed 

in the right half of the project window when you select the project icon. The objects 

at the top of this type of object hierarchy (libraries as well as projects) form the 

starting point in dialog boxes used to select objects. 

Project View 

You can display the project structure for the data available on the programming 

device in the component view "offline" and for the data available on the 

programmable control system in the component view "online" in project windows. 

An additional view you can set is available if the respective optional package is 

installed: the plant view. 

Note 

Configuring hardware and networks can only be done in the "offline" view. 

6.2 What You Should Know About Access Protection 

As of STEP 7 V5.4, you have the option of restricting access to projects and 

libraries by assigning a passwords to them. In order to do this, you must have 

installed "SIMATIC Logon". 

You can also enable, disable and display a change log. 

If SIMATIC Logon is installed on your computer, you will have access to the 

following menu commands in the SIMATIC Manager. You can use these 

commands to manage access protection for a project or library: 

• Access Protection, Enable 

• Access Protection, Disable 

• Access Protection, Manage Users 

• Access Protection, Adjust in Multiproject 

• Remove Access Protection und Change Log 

To enable access protection, go to the SIMATIC Manager and select the 

Options > Access Protection, Enable menu command. This menu command 

opens a dialog box in which you can enable access protection by assigning a 


6-2 A5E00706944-01


project password. Once the password has been assigned, this password will have 

to be entered before the project or library concerned can be edited. 

The Remove Access Protection and Change Log menu command removes 

access protection as well as the change log for a password-protected project or 

library. After having removed the access protection you can once again edit 

projects with a STEP 7 version prior to V5.4. 

Note 

• In order to enable or disable access protection, you must be authenticated in 

SIMATIC Logon as a project administrator. 

• When access protection is first enabled, the project format is changed. You will 

receive a message informing you that the changed project can no longer be 

edited with older versions of STEP 7. 

• The Options >Access Protection >Remove Access Protection and 

Change Log function allows projects or libraries to be once again edited with a 

STEP 7 version prior to V5.4. However, in this case, you will lose information 

about the users who have access to the project or library as well as all change 

logs. 

• The currently logged on user is shown in the status bar of the SIMATIC 

Manager. 

• The currently logged on project editor who enables the access protection is 

entered as the project administrator and is then prompted to assign a project 

password. 

• To open an access-protected project, you must be authenticated in 

SIMATIC Logon as a project administrator or project editor. Access protection 

must also be enabled or you must know the project password.. 


A5E00706944-01 6-3


6.3 What You Should Know About The Change Log 

As of STEP 7 V5.4, after setting up access protection for projects and libraries, you 

have the option of keeping a change log that records online actions. 

Examples: 

• Activate / Deactivate / Configure the access protection and change log 

• Open / Close projects and libraries 

• Download to PLC (system data) 

• Selected operations for loading and copying blocks 

• Activities for changing the operating mode 

• Clear/Reset 

You can display the change log and enter comments such as those explaining 

changes that you have made. For this functionality to be available, 

"SIMATIC Logon" must be installed. 

To enable the change log, go to the SIMATIC Manager and select the Options > 

Change Log, Enable menu command. After you have enabled the change log, 

your can view it (menu command: Options > Change Log, Display) or disable it 

(menu command: Options > Change Log, Disable. 

When you click on an object in the project structure (such as a project folder or 

subordinate station), the associated change log is displayed. 

Note 

• The Options > Access Protection > Remove Access Protection and 

Change Log function allows projects or libraries to be once again edited with a 

STEP 7 version prior to V5.4. However, in this case, you will lose information 

about the users who have access to the project or library as well as all change 

logs. 

• To execute this function, you must be authenticated as a project administrator 

in "SIMATIC Logon", and access protection for this project must be enabled 


6-4 A5E00706944-01


6.4 Using Foreign-Language Character Sets 

As of STEP 7 V5.3 SP2, you can enter texts in foreign languages in projects and 

libraries even if these languages do not match the language that has been set for 

STEP 7. To do this, the corresponding Windows language must be set in the 

Control Panel of the operating system. This makes it possible, for example, to 

operate STEP 7 in the STEP 7 language English on a Chinese-language version of 

Windows but still allows Chinese text be entered. 

In this case, the following types and options for language settings must be 

distinguished: 

Windows Language Setting 

This setting is made in the Windows Control Panel. Texts pertaining to the 

operating system are displayed in the language selected, and you can enter texts 

in foreign-language character strings. 

Project Language 

The project language is the language that is set in the Window Control Panel when 

a project is first created. Once chosen, this project language cannot be changed. 

However, with the "language-neutral" setting it is still possible to open a project on 

computers with other language settings in Windows. Before changing the project 

language to "language-neutral", make sure that only characters from the Englishlanguage 

character set (ASCII characters 0x2a - 0x7f) were previously used in the 

project when entering text. 

To find out the project language for a project or a library, select the Edit > Object 

Properties menu command. In the dialog box that is then displayed you can also 

select the "Can be opened under any Windows language setting (languageneutral)" 

option. 

If you copy a project by means of the Save As menu command and the project 

language is not the same as the current Windows language setting, you can then 

change the project language in the copied project to the language currently set in 

Windows. This will be useful in cases such as when you want to create languagespecific 

variants of a project. In this case, the master project should contain only 

characters from the English-language character set (ASCII characters 0x2a - 0x7f). 

This will ensure that data corruption will not occur when the language-specific 

project is edited further in the respective language. 

STEP 7 Language 

The STEP 7 language is the one that you set in the SIMATIC Manager by using the 

Options > Customize menu command. This language is the one use for interface 

elements, menu command, dialog boxes and error messages in STEP 7. 

If you are using another Windows language such as German, English, French, 

Italian or Spanish, you can ensure that the STEP 7 interface is correctly displayed 

by selecting English as the STEP 7 language. 


A5E00706944-01 6-5


Rules 

If you will be editing your projects or libraries on computers that have different 

language settings, be sure to observe the following "rules and regulations" to 

prevent incompatibilities or data corruption from occurring when using a foreignlanguage 

character set: 

• Install STEP 7 only in folders with names that contain the characters of the 

English character set (ASCII characters 0x2a - 0x7f). 

• Only use project names and project paths with names that contain the 

characters of the English character set (ASCII characters 0x2a - 0x7f). For 

example, if you use German umlauts, Cyrillic or Chinese characters, then the 

project can only be opened on computers that have a compatible language 

setting in Windows. 

• In multiprojects, only use projects and libraries with the same project language 

or those that are identified as being language-neutral ones. The multiproject 

itself is language-neutral. 

• When creating libraries, always make them language-neutral to ensure than 

they can be used on computers with different Windows language settings. 

When assigning names to library projects, entering comments, or creating 

symbol names, etc. be sure to only use ASCII characters (0x2a - 0x7f) so that 

the libraries can be used without any problems. 

• When importing/exporting hardware configurations or symbol tables, make sure 

that you only import/export language-compatible files. 

• In the names of user-defined attributes, use only characters from the Englishlanguage 

character set (ASCII characters 0x2a - 0x7f). 

• If, in an STL source, you are using characters that are not in the English 

character set (ASCII characters 0x2a - 0x7f) for the TITLE, AUTHOR, FAMILY 

block properties, then place these entries in single quote marks. 


6-6 A5E00706944-01


Notes 

• If you change or copy projects or libraries that were created on a computer that 

is identified as being language-neutral with respect to the Windows language 

setting but is not compatible with the setting on the computer currently being 

used, data corruption may occur if characters that are not contained in the 

English character set (ASCII characters 0x2a - 0x7f) were used in the project 

or library. 

For this reason, before editing "foreign" projects or libraries, make sure to 

check whether the Windows language setting on your computer matches the 

project language. 

• If you export hardware configurations or symbol tables that are to be imported 

in another Windows language setting, make sure that only characters from the 

English-language character set (ASCII characters 0x2a - 0x7f) were previously 

used and that no other language-specific characters such as German umlauts, 

Japanese characters or Cyrillic characters are present. 

• Exported hardware configurations or symbol tables that contain languagespecific 

characters such as German umlauts, Japanese characters or Cyrillic 

characters may only be imported in the same Windows language setting from 

which they were exported. This means that if you import older symbol tables 

that might contain such language-specific characters, be sure to check the 

results carefully: the symbols must be unique, must not contain any question 

marks or other incorrect characters, and must be plausible. 

• If symbol tables contain special characters that are not defined in ("known to") 

the current Windows language setting, then the question marks or other 

incorrect characters now part of the symbol names may cause problems and 

errors when sorting by names and comments. 

• Please note that with symbolic addressing the symbolic names must be written 

in quotation marks (""). 


To be able to enter text in foreign-language character sets in projects and libraries, 

proceed as follows: 

1. In the Windows Control Panel, set the language setting to the language 

desired. 

2. Create a project. 

3. Enter the text in foreign-language characters. 

For project and libraries that were created before STEP 7 V5.3 SP2, the project 

language is "not yet specified". In this case, you can select the Edit > Object 

Properties menu command to set the project language to the language currently 

set in Windows. Before doing so, make sure that the project does not contain any 

characters that are not defined in ("known to") the current Windows language 

setting. 


A5E00706944-01 6-7


6.5 Setting the MS Windows Language 

To set the Windows language, proceed as follows: 

Setting the Language in Windows XP and Windows Server 2003: 

1. To set the desired display language for programs that do not support Unicode, 

select the following menu command sequence: 

Control Panel > Regional and Language Options > Advanced > Language 

for non-Unicode programs. 

2. To set the input language (standard regional settings properties), select the 

following menu command sequence: 

Control Panel > Regional and Language Options > Languages > Details. 



Control Panel > Regional and Language Options > Regional Settings 

(Standards and Formats). 

You can enter texts in the desired language and display them correctly only after 

you have made all of these settings. 

Setting the Language in Windows 2000: 

1. To set the desired display language, select the following menu command 

sequence: 

Control Panel > Regional Settings > General > Your locale (location). 

2. To set the desired language, select the following menu command sequence: 

Control Panel > Regional Settings > General > Set as Default. 



Control Panel > Regional Settings > Input Locales. 

You can enter texts in the desired language and display them correctly only after 

you have made all of these settings. 


6-8 A5E00706944-01


6.6 Setting Up a Project 

6.6.1 Creating a Project 

To construct a solution to your automation task using the framework of a project 

management, you will need to create a new project. The new project is created in 

the directory you set for projects in the "General" tab when you selected the menu 

command Options > Customize. 

Note 

The SIMATIC Manager allows names that are longer than eight characters. The 

name of the project directory is, however, cut off to eight characters. Project names 

must therefore differ in their first eight characters. The names are not casesensitive. 

You will find a step-by-step guide to creating a project under Creating a Project 

Manually or under Creating a Project Using the Wizard. 

Creating a Project Using the Wizard 

The easiest way to create a new project is using the "New Project" wizard. Use the 

menu command File > "New Project" Wizard to open the wizard. The wizard 

prompts you to enter the required details in dialog boxes and then creates the 

project for you. In addition to the station, CPU, program folder, source file folder, 

block folder, and OB1 you can even select existing OBs for error and alarm 

processing. 

The following figure shows an example of a project created with the wizard. 

Creating a Project Manually 

You can also create a new project using the menu command File > New in the 

SIMATIC Manager. It already contains the "MPI Subnet" object. 


A5E00706944-01 6-9


Alternative Procedures 

When editing a project, you are flexible as to the order in which you perform most 

of the tasks. Once you have created a project, you can choose one of the following 

methods: 

• First configure the hardware and then create the software for it, or 

• Start by creating the software independent of any configured hardware. 

Alternative 1: Configure the Hardware First 

If you want to configure the hardware first, proceed as described in Volume 2 of the 

Configuring Hardware with STEP 7 Manual. When you have done this, the "S7 

Program" and "M7 Program" folders required to create software are already 

inserted. Then continue by inserting the objects required to create programs. Then 

create the software for the programmable modules. 

Alternative 2: Create Software First 

You can also create software without first having to configure the hardware; this 

can be done later. The hardware structure of a station does not have to be set for 

you to enter your programs. 

The basic procedure is as follows: 

1. Insert the required software folders (S7/M7 Program without a Station or CPU) 

in your project. 

Here you are simply deciding whether the program folder is to contain S7 

hardware or M7 hardware. 

2. Then create the software for the programmable modules. 

3. Configure your hardware. 

4. Once you have configured the hardware, you can link the M7 or S7 program to 

a CPU. 


6-10 A5E00706944-01


6.6.2 Inserting Stations 

In a project, the station represents the hardware structure of a programmable 

controller and contains the data for configuring and assigning parameters to 

individual modules. 

New projects created with the "New Project" wizard already contain a station. 

Otherwise you can create the station using the menu command Insert > Station. 

You can choose between the following stations: 

• SIMATIC 300 station 

• SIMATIC 400 station 

• SIMATIC H station 

• SIMATIC PC station 

• PC/programming device 

• SIMATIC S5 

• Other stations, meaning non- SIMATIC S7/M7 and SIMATIC S5 

The station is inserted with a preset name (for example, SIMATIC 300 Station(1), 

SIMATIC 300 Station(2), etc.). You can replace the name of the stations with a 

relevant name, if you wish. 

You will find a step-by-step guide to inserting a station under Inserting a Station. 

Configure the Hardware 

When you configure the hardware you specify the CPU and all the modules in your 

programmable controller with the aid of a module catalog. You start the hardware 

configuration application by double-clicking the station. 

For each programmable module you create in your configuration, an S7 or M7 

program and a connection table ("Connections" object) are created automatically 

once you have saved and exited the hardware configuration. Projects created with 

the "New Project" wizard already contain these objects. 

You will find a step-by-step guide to configuring under Configuring the Hardware, 

and detailed information under Basic Steps for Configuring a Station. 

Creating a Connection Table 

An (empty) connection table ("Connections" object) is created automatically for 

each programmable module. The connection table is used to define communication 

connections between programmable modules in a network. When it is opened, a 

window is displayed containing a table in which you define connections between 

programmable modules. 

You will find detailed information under Networking Stations within a Project. 

Next Steps 

Once you have created the hardware configuration, you can create the software for 

your programmable modules (Also refer to Inserting a S7/M7 Program). 


A5E00706944-01 6-11


6.6.3 Inserting an S7/M7 Program 

The software for programmable modules is stored in object folders. For SIMATIC 

S7 modules this object folder is called "S7 Program," for SIMATIC M7 modules it is 

called "M7 Program." 

The following figure shows an example of an S7 program in a programmable 

module in a SIMATIC 300 station. 

Existing Components 

An S7/M7 program is created automatically for each programmable module as a 

container for the software: 

The following objects already exist in a newly created S7 program: 

• Symbol table ("Symbols" object) 

• "Blocks" folder for containing the first block 

• "Source Files" folder for source files 

The following objects already exist in a newly created M7 program: 

• Symbol table ("Symbols" object) 

• "Blocks" folder 

Creating S7 Blocks 

You want to create Statement List, Ladder Logic, or Function Block Diagram 

programs. To do this, select the existing "Blocks" object and then select the menu 

command Insert > S7 Block. In the submenu, you can select the type of block you 

want to create (such as a data block, User-defined Data Type (UDT), function, 

function block, organization block, or variable table). 

You can now open the (empty) block and start entering the Statement List, Ladder 

Logic, or Function Block Diagram program. You will find more information on this in 

Basic Procedure for Creating Logic Blocks and in the Statement List, Ladder Logic, 

and Function Block Diagram manuals. 

Note 

The object "System Data" (SDB) which may exist in a user program was created 

by the system. You can open it, but you cannot make changes to it for reasons of 

consistency. It is used to make changes to the configuration once you have loaded 

a program and to download the changes to the programmable controller. 


6-12 A5E00706944-01


Using Blocks from Standard Libraries 

You can also use blocks from the standard libraries supplied with the software to 

create user programs. You access the libraries using the menu command File > 

Open. You will find further information on using standard libraries and on creating 

your own libraries in Working with Libraries and in the online help. 

Creating Source Files/CFC Charts 

You want to create a source file in a particular programming language or a CFC 

chart. To do this, select the "Source Files" or "Charts" object in the S7 program and 

then select the menu command Insert > S7 Software. In the submenu, you can 

select the source file that matches your programming language. You can now open 

the empty source file and start entering your program. You will find more 

information under Basic Information on Programming in STL Source Files. 

Creating Programs for M7 

You want to create programs for the operating system RMOS for a programmable 

module from the M7 range. To do this, select the M7 program and then select the 

menu command Insert > M7 Software. In the submenu, you can select the object 

that matches your programming language or operating system. You can now open 

the object you created to access the relevant programming environment. 

Creating a Symbol Table 

An (empty) symbol table ("Symbols" object) is created automatically when the 

S7/M7 program is created. When you open the symbol table, the "Symbol Editor" 

window opens displaying a symbol table where you can define symbols. You will 

find more information under Entering Multiple Shared Symbols in the Symbol 

Table. 

Inserting External Source Files 

You can create and edit source files with any ASCII editor. You can then import 

these files into your project and compile them to create individual blocks. 

The blocks created when the imported source file is compiled are stored in the 

"Blocks" folder. 

You will find more information under Inserting External Source Files. 

S7/M7 Program without a Station or CPU 


A5E00706944-01 6-13


6.7 Editing a Project 

Opening a Project 

To open an existing project, enter the menu command File > Open. Then select a 

project in the dialog boxes that follow. The project window is then opened. 

Note 

If the project you require is not displayed in the project list, click on the "Browse" 

button. In the browser you can then search for other projects and include any 

projects you find in the project list. You can change the entries in the project list 

using the menu command File > Manage. 

Copying a Project 

You copy a project by saving it under another name using the menu command 

File > Save As. 

You copy parts of a project such as stations, programs, blocks etc. using the menu 

command Edit > Copy. 

You will find a step-by-step guide to copying a project under Copying a Project and 

Copying Part of a Project. 

Deleting a Project 

You delete a project using the menu command File > Delete. 

You delete parts of a project such as stations, programs, blocks etc. using the 

menu command Edit > Delete. 

You will find a step-by-step guide to deleting a project under Deleting a Project and 

Deleting Part of a Project. 


6-14 A5E00706944-01


6.7.1 Checking Projects for Software Packages Used 

If a project that you are editing contains objects that were created with another 

software package, this software package is required to edit this project. 

No matter what programming device you are using to work with multiprojects, 

projects or libraries, STEP 7 assists you by showing you what software packages 

and versions are required to do so. 

This information on the software packages required is complete under the following 

conditions: 

• If the project (or all projects in a multiproject) or library was created in STEP 7 

as of V5.2. 

• If you yourself have checked the project for any software packages used in 

creating it. To do this, first go to the SIMATIC Manager and select the project 

concerned. Then select the menu command Edit > Object Properties. In the 

dialog box that is displayed, select the "Required software packages" tab. The 

information in this tab will tell you whether you should check the project for 

software packages. 

6.8 Managing Multilingual Texts 

STEP 7 offers the possibility of exporting text that has been created in a project in 

one language, having it translated, re-importing it, and displaying it in the translated 

language. 

The following text types can be managed in more than one language: 

• Titles and comments 

- Block titles and block comments 

- Network titles and network comments 

- Line comments from STL programs 

- Comments from symbol tables, variable declaration tables, user-defined 

data types, and data blocks 

- Comments, state names, and transition names in HiGraph programs 

- Extensions of step names and step comments in S7-Graph programs 

• Display texts 

- Message texts generated by STEP 7, S7-Graph, S7-HiGraph, S7-PDIAG 

or ProTool 

- System text libraries 

- User-specific text libraries 

- Operator-relevant texts 

- User texts 


A5E00706944-01 6-15


Export 

Exporting is done for all blocks and symbol tables located under the selected 

object. An export file is created for each text type. This file contains a column for 

the source language and a column for the target language. Text in the source 

language must not be changed. 

Import 

During import, the contents of the target-language columns (right-hand column) are 

integrated into the selected object. Only those translations whose source text 

(exported text) match an existing text in the "Source Language column are 

accepted. 

Changing Languages 

When changing languages, you can choose from all the languages that were 

specified during import into the selected project. The language change for "Title 

and Comments" is only applied to the selected object. A language change for 

"Display Texts" is always applied to the complete project. 

Deleting a Language 

When a language is deleted all the texts in this language are deleted from the 

internal database. 

One language should always be available as a reference language in your project. 

This can, for example, be your local language. This language should not be 

deleted. During exporting and importing always specify this reference language as 

the source language. The target language can be set as desired. 

Reorganize 

During reorganization, the language is changed to the language currently set. The 

currently set language is the language that you selected as the "Language for 

future blocks". Reorganization only affects titles and comments. 

Comment Management 

You can specify how comments for blocks should be managed in projects with 

texts being managed in many languages. 


6-16 A5E00706944-01



 

 

 

 

 

 

 

 

 

 

6.8.1 Types of Multilingual Texts 

For export, a separate file will be created for each type of text. This file will have 

the text type as its name and the export format as its extension (texttype.format: for 

example, SymbolComment.CSV or SymbolComment.XLS). Files that do not satisfy 

the naming convention cannot be used as source or target. 

The translatable text within a project is divided into the following text types: 

Text Type 

BlockTitle 

BlockComment 

NetworkTitle 

NetworkComment 

LineComment 

InterfaceComment 

SymbolComment 

S7UserTexts 

S7SystemTextLibrary 

S7UserTextLibrary 

Description 

Block title 

Block comments 

Network title 

Network comments 

Line comments in STL 

Var_Section comments (declaration tables in code 

blocks) and 

UDT comments (user-defined data types) and 

Data block comments 

Symbol comments 

Texts entered by the user which can be output on 

display devices 

Texts of system libraries which are integrated into 

messages can be updated dynamically during 

runtime, and displayed on the PG or other display 

devices 

Texts of user libraries which are integrated into 

messages can be updated dynamically during 

runtime, and displayed on the PG or other display 

devices 


A5E00706944-01 6-17


Text Type 

HiGraphStateName 

HiGraphStateComment 

Description 

S7-HiGraph 

State name 

State comment 

HiGraphTansitionName 

HiGraphTransitionComment 

S7GraphStateName 

S7GraphStateComment 

Transition name 

Transition comment 

S7-Graph 

Step name extension 

Step comment 

Editors in other optional packages (such as ProTool, WinCC, etc.) may have other 

application-specific text types that are not described here. 

6.8.2 Structure of the Export File 

The export file is structured as follows: 

Example: 

Fundamentally, the following applies: 

1. The following may not be changed, overwritten, or deleted: 

- Fields beginning with "$_" (these are keywords) 

- The numbers for the language (in the example above: 9(1) for the source 

language English (USA) and 7(1) for the target language German). 

2. Each file holds the text for just a single test type. In the example, the text type 

is NetworkTitle ($_Type(NetworkTitle). The rules for the translator who will edit 

this file are contained in the introductory text of the export file itself. 

3. Additional information regarding the text or comments must always appear 

before the type definition ($_Type…) or after the last column. 


6-18 A5E00706944-01


Note 

If the column for the target language has been overwritten with "512(32) $_Undefined," no 

target language was specified when the file was exported. To obtain a better overview, you 

can replace this text with the target language, for example, "9(1) English (US)" When 

importing the translated files, you must verify the proposed target language and, if 

necessary, select the correct language. 

You can hide text not to be displayed in the target language by entering the keyword $_hide. 

This does not apply to comments on variables (InterfaceComment) and to symbols 

(SymbolComment). 

Export File Format 

You specify the format in which export files are to be saved. 

If you have decided to use CSV format, you must keep in mind when editing in 

Excel that a CSV file can be only opened properly in Excel if the Open dialog is 

used. Opening a CSV file by double-clicking in Explorer often results in an 

unusable file. You will find it easier to work with CSV files in Excel if you use the 

following procedure: 

1. Open the export file in Excel 

2. Save the files as XLS files 

3. Translate the text in the XLS files 

4. Save the XLS files in Excel in CSV format. 

Note 

Export files may not be renamed. 

6.8.3 Managing User Texts Whose Language Font is Not Installed 

You can export user texts whose language font is not installed in your operating 

system, have them translated and then import them back in and save them for use 

in your project. 

However, such texts can only be displayed on a computer that has the appropriate 

language font installed on it. 

For example, if you have user texts that have to be translated into Russian and do 

not have a Cyrillic font installed on you operating system, proceed as follows: 

1. Export the user text to be translated with the source language "English" and 

target language "Russian". 

2. Send the export files to the translator, who will definitely have a Cyrillic font 

available. 

3. Import the translated export files. 

Result: The project is now available in English and Russian on you computer. 

4. Save the whole project and send it to the customer who will use the Russian 

texts and will thus have a Cyrillic font available to display them. 


A5E00706944-01 6-19


6.8.4 Information on the Log File 

Error messages and warnings that appear when working with text managed in 

many languages are output in a log file (TXT format). This file is stored in the same 

folder as the export files. 

In general, the messages are self-explanatory. Any further explanations are listed 

below: 

Warning 

The text 'xyz' is already present in file 'xyz'. Any further occurrence of this text will 

be ignored. 

Explanation 

Regardless of its language, a text is used as the basis for the translation. If an 

identical text is used for different terms in more than one language or more than 

once in one language, it can no longer be uniquely identified and will thus not be 

translated. 

Example: 

This only applies to titles and comments. 

Remedy 

Rename the texts concerned in the exported file (in the example, a single German 

word must be used instead of three different ones), and then re-import the texts. 


6-20 A5E00706944-01


6.8.5 Optimizing the Source for Translation 

You can prepare the source material for translation by combining different terms 

and expressions. 

Example 

Before preparation (export file): 

 

 

 

 

 

 

 

 

 

Combining to a single expression: 

 

 

 

 

 

 

 

 

 

 

 

 

After preparation (that is, after import and subsequent export): 

$_Languages 

9 (1) English (USA) 

$_Type(SymbolComment) 

Auto-enable 

9 (1) English (USA) 

Auto-enable 

Source Language 

Target Language 


A5E00706944-01 6-21


6.8.6 Optimizing the Translation Process 

If you have projects where the structure and text are similar to a previous project, 

you can optimize the translation process. 

In particular, the following procedure is recommended for projects that were 

created by copying and then modifying. 

Prerequisite 

There must be an existing translated export target. 

Procedure 

1. Copy the export files into the project folder for the new project to be translated. 

2. Open the new project and export the text (menu command Options > Manage 

Multilingual Texts > Export). Since the export target already exists, you will 

be asked whether the export target should be extended or overwritten. 

3. Click on the Add button. 

4. Have the export files translated (only new text needs to be translated). 

5. Then import the translated files. 


6-22 A5E00706944-01


6.9 Micro Memory Card (MMC) as a Data Carrier 

6.9.1 What You Should Know About Micro Memory Cards (MMC) 

Micro Memory Cards (MMC) are plug-in memory cards, for example, for a 

CPU 31xC or an IM 151/CPU (ET 200S). Their most distinguishing feature is the 

highly compact design. 

A new memory concept has been introduced for MMCs. It is briefly described 

below. 

Content of the MMCs 

The MMC serves as both the load memory and a data storage device (data 

carrier). 

MMC as Load Memory 

The MMCs contain the complete load memory for an MMC-compatible CPU. The 

load memory contains the program with the blocks (OBs, DBs, FCs, ...) as well as 

the hardware configuration. The contents of the load memory influence the 

functioning of the CPU. In the MMC's function as load memory, blocks and the 

hardware configuration with loading functions can be transferred from it (i.e. 

Download to CPU). Blocks downloaded to the CPU take effect immediately; 

however, the hardware configuration does so only after the CPU is restarted. 

Response to Memory Reset 

The blocks stored on the MMC are retained after a memory reset. 

Loading and Deleting 

You can overwrite the blocks on the MMC. 

You can erase the blocks on the MMC. 

You cannot restore overwritten or erased blocks. 

Accessing Data Blocks on the MMC 

On the MMC, you can use data blocks and data block contents to handle larger 

quantities of data or data rather scarcely required in the user program. New 

system operations are available for that purpose: 

• SFC 82: creating data blocks in the load memory 

• SFC 83: reading from the data block in the load memory 

• SFC 84: writing to a data block in the load memory 


A5E00706944-01 6-23


MMC and Password Protection 

If a CPU (i.e. a CPU in the 300-C family) that is fitted with a Micro Memory Card 

(MMC) is password-protected, then the user will also be prompted to enter this 

password when opening this MMC in the SIMATIC Manager (on a programming 

device/PC). 

Displaying Memory Assignment in STEP 7 

The display of the load memory assignment in the module status dialog ("Memory" 

tab) shows both the EPROM and the RAM area. 

Blocks on MMCs show a 100% EPROM behavior. 


6-24 A5E00706944-01


6.9.2 Using a Micro Memory Card as a Data Carrier 

A SIMATIC Micro Memory Card (MMC) can be used with STEP 7 in the same 

manner as any other type of external data storage medium. 

After you have determined that the MMC has enough capacity to accommodate all 

the data to be stored, you can transfer any data visible in the operating system's 

file explorer to the MMC. 

In this way, you can make additional drawings, service instructions and functional 

descriptions pertaining to your plant available to other personnel. 

6.9.3 Memory Card File 

Memory Card files (*.wld) are generated for the 

• Software PLC WinLC (WinAC Basis and WinAC RTX) and 

• SlotPLCs CPU 41x-2 PCI (WinAC Slot 412 and WinAC Slot 416). 

The blocks and system data for a WinLC or CPU 41x-2 PCI can be saved in a 

Memory Card file as in an S7-Memory Card. The contents of these files then 

correspond to the contents of a corresponding Memory Card for a S7-CPU. 

This file can then be downloaded by a menu command of the operating panel of 

the WinLC or CPU 41x-2 PCI into their download memories, corresponding to the 

downloading of the user program with STEP 7. 

In the case of the CPUs 41x-2 PCI this file can be downloaded automatically when 

the PC operating system is started up, if the CPU 41x-2 PCI is not buffered and is 

only operated with a RAM Card ("Autoload" function). 

Memory Card files are "normal" files in the sense of Windows, which can be 

moved, deleted or transported with a data medium with the Explorer. 

For further information please refer to the corresponding documentation of the 

WinAC products. 


A5E00706944-01 6-25


6.9.4 Storing Project Data on a Micro Memory Card (MMC) 

With STEP 7 you can store the data for your STEP 7 project as well as any other 

kind of data (such as WORD or Excel files) on a SIMATIC Micro Memory Card 

(MMC) in a suitable CPU or a programming device (PG)/PC. This allows you to 

access project data with programming devices that do not have the project saved 

on them. 

Requirements 

You can only store project data on an MMC if it is inserted in the slot of a suitable 

CPU or a programming device (PG)/PC and there is an online connection 

established. 

Be sure that the MMC has enough capacity to accommodate all the data to be 

stored on it. 

Data that can be stored on an MMC 

After you have determined that the MMC has enough capacity to accommodate all 

the data to be stored, you can transfer all data visible in the operating system's file 

explorer to the MMC. These data can include the following: 

• Complete project data for STEP 7 

• Station configurations 

• Symbol tables 

• Blocks and sources 

• Texts managed in many languages 

• Any other kinds of data, such as WORD or Excel files 


6-26 A5E00706944-01

7 Editing Projects with Different Versions of 

STEP 7 

7.1 Editing Version 2 Projects and Libraries 

Version V5.2 of STEP 7 no longer supports Changes in V2 Projects. When you 

edit V2 projects or libraries, inconsistencies can occur such that V2 projects or 

libraries can no longer be edited with older versions of STEP 7. 

In order to continue to edit V2 projects or libraries, a STEP 7 version older that 

V5.1 must be used. 

7.2 Expanding DP Slaves That Were Created with Previous 

Versions of STEP 7 

Constellations That Can Be Formed by Importing New *.GSD Files 

New DP slaves can be accepted by the HW Config if you install new device 

database files (*.GSD files) into the Hardware Catalog. After installation, they are 

available in the Other Field Devices folder. 

You cannot reconfigure or expand a modular DP slave in the usual manner if all of 

the following conditions exist: 

• The slave was configured with a previous version of STEP 7. 

• The slave was represented in the Hardware Catalog by a type file rather than a 

*.GSD file. 

• A new *.GSD file was installed over the slave. 

Remedy 

If you want to use the DP slave with new modules that are described in the *.GSD 

file: 

• Delete the DP slave and configure it again. Then the DP slave is described 

completely by the *.GSD file, not by the type file. 

If you do not want to use any new modules that are described only in the *.GSD 

file: 

• Under PROFIBUS-DP in the Hardware Catalog window, select the "Other 

FIELD DEVICES/Compatible PROFIBUS-DP Slaves" folder. STEP 7 moves the 

"old" type files into this folder when they are replaced by new *.GSD files. In this 

folder you will find the modules with which you can expand the already 

configured DP slave. 


A5E00706944-01 7-1

Editing Projects with Different Versions of STEP 7 

Constellation after Replacement of Type Files by GSD Files in STEP 7 V5.1 

Service Pack 4 

As of STEP 7 V5.1, Service Pack 4, the type files have been either updated or 

largely replaced by GSD files. This replacement only affects the catalog profiles 

supplied with STEP 7, not any catalog profiles that you may have created yourself. 

DP slaves whose properties were previously determined by type files and are now 

determined by GSD files are still located in the same place in the hardware catalog. 

The "old" type files were not deleted but moved to another place in the hardware 

catalog. They are now located in the catalog folder "Other field 

devices\Compatible PROFIBUS DP slaves\...". 

Expanding an Existing DP Configuration with STEP 7, as of V5.1 Service Pack 4 

If you edit a project that was created with a previous version of STEP 7 (earlier 

than V5.1, SP4) and you want to expand a modular DP slave, then you cannot use 

the modules or submodules taken from the usual place in the hardware catalog. In 

this case, use the DP slave found at "Other FIELD DEVICES\Compatible 

PROFIBUS DP slaves\...". 

Editing a DP Configuration with an Earlier Version of STEP 7 V5.1, SP4) 

If you configure an "updated" DP slave with STEP 7 as of V5.1, Service Pack 4 and 

then edit the project with a previous version of STEP 7 (earlier than STEP 7 V5.1, 

SP4), you will not be able to edit this DP slave since the GSD file used is unknown 

to the previous version. 

Remedy: You can install the required GSD file in the previous version of STEP 7. 

In this case, the GSD file is stored in the project. If the project is subsequently 

edited with the current STEP 7 version will use the newly installed GSD file for the 



7-2 A5E00706944-01


7.3 Editing Current Configurations with Previous Versions 

of STEP 7 

Configuring Direct Data Exchange (Lateral Communication) 

Configuring direct data exchange with a DP master without a DP master system: 

• Not possible with STEP7 V5.0, Service Pack 2 (or older version) 

• Possible with STEP7 V5.0, as of Service Pack 3 and as of STEP 7 V5.1 

If you save a DP master without its own DP master system with configured 

assignments for direct data exchange and you continue to edit this project with an 

older version of STEP 7 V5 (STEP 7 V5.0, Service Pack 2 (or older)), the following 

effects can occur: 

• A DP master system is displayed with slaves that are used for a STEP 7- 

internal data storage area of the assignments for direct data exchange. These 

DP slaves do not belong to the displayed DP master system. 

• You cannot connect a new or an orphaned DP master system to this DP 

master. 

Online Connection to the CPU by Means of a PROFIBUS-DP Interface 

Configuring the PROFUBUS-DP interface without a DP master system: 

• STEP7 V5.0, Service Pack 2 (or older): a connection to the CPU by means of 

this interface is not possible. 

• As of STEP7 V5.0, Service Pack 3: During compilation, system data for the 

PROFIBUS-DP interface are generated; a connection to the CPU by means of 

this interface is possible after downloading. 


A5E00706944-01 7-3


7.4 Appending SIMATIC PC Configurations of Previous 

Versions 

PC Configurations of STEP 7 V5.1 Projects (up to SP 1) 

As of STEP 7 V5.1, Service Pack 2 you can download communications to the PC 

station in the same way as to an S7-300 or S7-400 station (without having to take 

the roundabout via configuration file). Nevertheless, a configuration file is always 

generated during a storing or compiling operation in order to enable the 

transmission of the configuration to the target PC station using this method. 

This bears the consequence that "older" PC stations cannot interpret some of the 

information included in the newly generated configuration files. STEP 7 

automatically adapts itself to this circumstance: 

• If you create a new SIMATIC PC station configuration with STEP 7 as of V5.1, 

Service Pack 2, STEP 7 assumes that the target PC station was configured with 

the help of SIMATIC NET CD as of 7/2001, that is, under the presumption that 

S7RTM (Runtime Manager) is installed. The configuration files are generated in 

such a way that they can be interpreted by a "new" PC station. 

• If you append a SIMATIC PC station configuration of a previous version (for 

example, the PC station was configured with STEP 7 V5.1, Service Pack 1),. 

STEP 7 does not presume that the target PC station was configured with the 

help of SIMATIC NET CD as of 7/2001. Those configuration files are then 

generated in such a way that they can be interpreted by an "old" PC station. 

If this default behavior does not match your requirements, you can modify it as 

described below: 

Setting in the Context Menu "Configuring Hardware ": 

1. Open the PC station hardware configuration 

2. Right-click on the station window (white area) 

3. Select the context-sensitive menu "Station Properties" 

4. Check or clear the "Compatibility" checkbox. 

Setting in the Context Menu "Configuring Networks" 

1. Open the network configuration 

2. Highlight the PC station 

3. Select the menu command Edit > Object properties 

4. In the dialog, select the "Configuration" tab 

5. Check or clear the "Compatibility" checkbox. 


7-4 A5E00706944-01


PC Configurations of STEP 7 V5.0 Projects 

You must convert the station if you want to edit a SIMATIC PC station configuration 

with STEP 7 as of V5.0, Service Pack 3 to configure new components that are only 

supported by Service Pack 3 or higher: 

1. In the SIMATIC Manager, highlight the SIMATIC PC station and select the 

menu command Edit > Object properties. 

2. In the "Functions" tab of the properties dialog, click on the "Expand" button. 

The SIMATIC PC station is then converted. Now, it can only be edited with 

STEP 7 V5.0, Service Pack 3 or later versions. 


A5E00706944-01 7-5


7.5 Displaying Modules Configured with Later STEP 7 

Versions or Optional Packages 

As of STEP 7 V5.1 Service Pack 3, all modules are displayed, even those that 

were configured with a later STEP 7 version and are thus unknown to the "older" 

STEP 7. Modules configured with an optional package are also displayed, even if 

the required corresponding optional package is not installed on the programming 

device (PG) used to open the given project. 

In previous STEP 7 versions, such modules and their subordinate objects were not 

displayed. In the current version, these objects are visible and can be edited to 

certain extent. For example, you can use this function to also change user 

programs, even if the project was created on another computer running a newer 

version of STEP 7 and the module (such as a CPU) cannot be configured with the 

existing earlier STEP 7 version because this module has new properties and new 

parameters. 

The module "unknown" to STEP 7 is displayed as a generic, representative module 

with the following icon: 

If you open the project with the appropriate STEP 7 version or with a compatible 

optional package, all modules are displayed their standard way and there are no 

restrictions on editing. 

PG with latest STEP 7 / with 

optional package 

PG with older STEP 7 / without 

optional package 

Represented by "known", latest 

module 

>>>---Project data--->>> 

Represents the latest module as an 

"unknown" module 


7-6 A5E00706944-01


Working with a Representative Module in the SIMATIC Manager 

The representative module is visible below the station level. All subordinate objects 

at this level such as user programs, system data and connection tables are visible 

and can be downloaded from the SIMATIC Manager. 

You also open, edit, compile and load the user program (such as its blocks). 

However, the following restrictions apply to projects with representative blocks: 

• You cannot copy a station containing a representative block. 

• In the menu command "Save project as..." the option "with reorganization" 

cannot be applied completely. 

The representative module and all references and subordinate objects of this 

modules will be missing in the copied and reorganized project (for example, the 

user program). 

Working with a Representative Module in the Hardware Configuration 

The representative module is displayed at the slot where it was configured. 

You can open this module, but you cannot change its parameters or download to it. 

The module properties are limited to those given in the "Representative" tab 

property sheet. The station configuration can not be changed (such as by adding 

new modules). 

Hardware diagnostics (such as opening a station online) are also possible (to a 

limited extent: new diagnostic options and texts are not recognized.). 

Working with a Representative Module in the Network Configuration 

The representative module is also displayed in NetPro. In this case, the name of 

the module on the station is preceded by question mark. 

A project with a representative module can only be opened write-protected in 

NetPro. 

If you open the project in write-protected mode, you can display and print the 

network configuration. You can also obtain the connection status, which will at least 

contain the information supported by the STEP 7 version being used. 

In general, however, you cannot make any changes or save, compile or download 

them. 

Subsequent Installation of Modules 

If the module is from a later version of STEP 7 and there is a HW update available 

for it, you can replace the representative module with the "real" one. Upon opening 

the station, you receive information on the necessary HW updates or optional 

packages, and you can install them using the dialog. As an alternative, you can 

install these modules by selecting the menu command Options > Install HW 

Updates. 


A5E00706944-01 7-7



7-8 A5E00706944-01

8 Defining Symbols 

8.1 Absolute and Symbolic Addressing 

In a STEP 7 program you work with addresses such as I/O signals, bit memory, 

counters, timers, data blocks, and function blocks. You can access these 

addresses in your program absolutely, but your programs will be much easier to 

read if you use symbols for the addresses (for example, Motor_A_On, or other 

identifiers according to the code system used within your company or industry). An 

address in your user program can then be accessed via this symbol. 

Absolute Addresses 

An absolute address comprises an address identifier and a memory location (for 

example, Q 4.0, I 1.1, M 2.0, FB21). 

Symbolic Addresses 

You can make your program easier to read and simplify troubleshooting if you 

assign symbolic names to the absolute addresses. 

STEP 7 can translate the symbolic names into the required absolute addresses 

automatically. If you would prefer to access ARRAYs, STRUCTs, data blocks, local 

data, logic blocks, and user-defined data types using symbolic names, you must 

first assign symbolic names to the absolute addresses before you can address the 

data symbolically. 

You can, for example, assign the symbolic name MOTOR_ON to the address Q 

4.0 and then use MOTOR_ON as an address in a program statement. Using 

symbolic addresses it is easier to recognize to what extent the elements in the 

program match the components of your process control project. 

Note 

Two consecutive underline characters (for example, MOTOR__ON) are not 

permitted in a symbolic name (variable ID). 


A5E00706944-01 8-1

Defining Symbols 

Support with Programming 

In the programming languages Ladder Logic, Function Block Diagram, and 

Statement List you can enter addresses, parameters, and block names as absolute 

addresses or as symbols. 

Using the menu command View > Display > Symbolic Representation you can 

toggle between the absolute and symbolic representation of addresses. 

To make it easier to program using symbolic addresses you can display the 

absolute address and the symbol comment that belongs with the symbol. You can 

activate this information using the menu command View > Display > Symbol 

Information. This means that the line comment following every STL statement 

contains more information. You cannot edit the display; you must make any 

changes in the symbol table or the variable declaration table. 

The following figure shows you the symbol information in STL. 

When you print out a block, the current screen representation with statement 

comments or symbol comments is printed. 


8-2 A5E00706944-01


8.2 Shared and Local Symbols 

A symbol allows you to work with meaningful symbolic names instead of absolute 

addresses. The combination of short symbols and longer comments can be used 

effectively to make programming easier and program documentation better. 

You should distinguish between local (block-specific) and shared symbols. 

Shared Symbols 

Validity • Is valid in the whole user program, 

• Can be used by all blocks, 

• Has the same meaning in all blocks, 

• Must be unique in the whole user program. 

Permitted • Letters, numbers, special characters, 

characters • Accents other than 0x00, 0xFF, and 

quotation marks, 

• The symbol must be placed within quotation 

marks if you use special characters. 

Use • You can define shared symbols for: 

• I/O signals (I, IB, IW, ID, Q, QB, QW, QD) 

• I/O inputs and outputs (PI, PQ) 

• Bit memory (M, MB, MW, MD) 

• Timers (T)/ counters (C) 

• Logic blocks (OB, FB, FC, SFB, SFC) 

• Data blocks (DB) 

• User-defined data types (UDT) 

• Variable table (VAT) 

Local Symbols 

• Only known to the block in 

which it was defined, 

• The same symbol can be used 

in different blocks for different 

purposes. 

• Letters, 

• Numbers, 

• Underscore (_). 

• You can define local symbols 

for: 

• Block parameters (input, 

output, and in/out parameters), 

• Static data of a block, 

• Temporary data of a block. 

Defined where? Symbol table Variable declaration table for the 

block 


A5E00706944-01 8-3


8.3 Displaying Shared or Local Symbols 

You can distinguish between shared and local symbols in the code section of a 

program as follows: 

• Symbols from the symbol table (shared) are shown in quotation marks "..". 

• Symbols from the variable declaration table of the block (local) are preceded by 

the character "#". 

You do not have to enter the quotation marks or the "#". When you enter your 

program in Ladder, FBD, or STL the syntax check adds these characters 

automatically. 

If you are concerned that there may be some confusion because, for example, the 

same symbols are used in both the symbol table and the variable declaration, you 

must code the shared symbol explicitly when you want to use it. Any symbols 

without the respective coding are interpreted as block-specific (local) variables in 

this case. 

Coding shared symbols is also necessary if the symbol contains blanks. 

When programming in an STL source file the same special characters and 

guidelines for their use apply. Code characters are not added automatically in freeedit 

mode, but they are still necessary if you wish to avoid confusion. 

Note 

Using the menu command View > Display > Symbolic Representation you can 

toggle the display between the declared shared symbolic and the absolute 

addresses. 


8-4 A5E00706944-01


8.4 Setting the Address Priority (Symbolic/Absolute) 

The address priority helps you to adapt the program code as you see fit when 

making changes in the symbol table, changing parameter names of data blocks or 

function blocks or when changing UDTs referring to component names or changing 

multiple instances 

When making changes in the following situations, be sure to set the address 

priority carefully and with a definite purpose in mind. In order for you to benefit from 

address priority, each change procedure must be completed in itself before you 

start with another type of change. 

To set the address priority, go to the SIMATIC Manager and select the block folder 

and then select the menu command Edit > Object Properties. In the "Address 

Priority" tab, you can make the settings that you deem appropriate. 

Making optimal settings in address priority requires that the following situations for 

making a change be distinguished: 

• Correction of Individual Names 

• Switching Names or Assignments 

• New Symbols, Variables, Parameters or Components 

Note 

Please be aware that the absolute block number is the determining factor when 

making block calls ("Call FC" or "Call FB, DB") for the logic block – even when 

symbolic address priority has been set! 

Correction of Individual Names 

Examples: 

In the symbol table or in the program editor/block editor a spelling error in a name 

has to be corrected. This applies to all names in the symbol table as well as to all 

the names of parameters, variables or components that can be changed with the 

program editor/block editor. 


A5E00706944-01 8-5


Setting the Address Priority: 

Tracking Changes: 

In the SIMATIC Manager, select the block folder and then select the menu 

command Edit > Check Block Consistency. The "Check block consistency' 

function make the changes necessary in the individual blocks. 

Switching Names or Assignments 

Examples: 

• The names of existing assignments in the symbol table are switched. 

• Existing assignments in the symbol table are assigned new addresses. 

• Variable names, parameter names or component names are switched in the 

program editor/block editor. 



8-6 A5E00706944-01



• In the SIMATIC Manager, select the block folder and then select the menu 

command Edit > Check Block Consistency. The "Check block consistency" 


New Symbols, Variables, Parameters or Components 

Examples: 

• You are creating new symbols for addresses used in the program. 

• You are adding new variable or parameters to data blocks, UDTs or function 

blocks. 


• For changes in the symbol table. 

• For changes in the program/block editor. 


A5E00706944-01 8-7



In the SIMATIC Manager, select the block folder and then select the menu 

command Edit > Check Block Consistency. The "Check block consistency' 



8-8 A5E00706944-01


8.5 Symbol Table for Shared Symbols 

Shared symbols are defined in the symbol table. 

An (empty) symbol table ("Symbols" object) is created automatically when you 

create an S7 or M7 program. 

Validity 

The symbol table is only valid for the module to which you link the program. If you 

want to use the same symbols in a number of different CPUs, you yourself must 

ensure that the entries in the various symbol tables all match up (for example, by 

copying the table). 

8.5.1 Structure and Components of the Symbol Table 

Structure of the Symbol Table 

Row 

If the columns for "Special Object Properties" were hidden (the menu command View > 

Columns O, M, C, R, CC was deselected), this symbol appears in the row if the row 

concerned has at least one "Special Object Property" set for it. 

"Status" Column 

The symbol name or address is identical to another entry in the symbol table. 

The symbol is still incomplete (the symbol name or the address is missing). 


A5E00706944-01 8-9


R/O/M/C/CC Columns 

The columns R/O/M/CC show whether a symbol was assigned special object 

properties (attributes): 

• R (monitoring) means that error definitions for process diagnostics were created 

for the symbol with the optional package S7-PDIAG (V5). 

• O means that the symbol can be operated and monitored with WinCC. 

• M means that a symbol-related message (SCAN) was assigned to the symbol. 

• C means that the symbol is assigned communication properties. 

• CC means that the symbol can be quickly and directly monitored and controlled 

in the program editor ('Control at Contact'). 

Click on the check box to enable or disable these "special object properties". You 

can also edit the "special object properties" via Edit > Special Object Properties 

menu command 

"Symbol" Column 

The symbolic name must not be longer than 24 characters. 

You cannot assign symbols in the symbol table for addresses in data blocks (DBD, 

DBW, DBB, DBX). Their names are assigned in the data block declaration. 

For organization blocks (OB) and some system function blocks (SFB) and system 

functions (SFC), predefined symbol table entries already exist which you can 

import into the table when you edit the symbol table of your S7 program. The 

import file is stored in the STEP 7 directory under ...\S7data\Symbol\Symbol.sdf. 

"Address" Column 

An address is the identifier for a particular memory area and memory location. 

Example: Input I 12.1 

The syntax of the address is checked as it is entered. 

"Data Type" Column 

You can choose between a number of data types available in STEP 7. The data 

type field already contains a default data type which you may change, if necessary. 

If the change you make is not suitable for the address or its syntax is incorrect, an 

error message appears as you exit the field. 

"Comment" Column 

You can assign comments to all symbols. The combination of brief symbolic names 

and more detailed comments makes creating programs more effective and makes 

your program documentation more complete. A comment can be up to 80 

characters in length. 

Converting to C Variables 

You can select symbols in the symbol table for an M7 program and convert them to 

corresponding C variables in conjunction with the ProC/C++ software option. 


8-10 A5E00706944-01


8.5.2 Addresses and Data Types Permitted in the Symbol Table 

Only one set of mnemonics can be used throughout a symbol table. Switching 

between SIMATIC (German) and IEC (English) mnemonics must be done in the 

SIMATIC Manager using the menu command Options > Customize in the 

"Language" tab. 

IEC SIMATIC Description Data Type Address 

Range 

I E Input bit BOOL 0.0 to 65535.7 

IB EB Input byte BYTE, CHAR 0 to 65535 

IW EW Input word WORD, INT, S5TIME, DATE 0 to 65534 

ID ED Input double word DWORD, DINT, REAL, TOD, TIME 0 to 65532 

Q A Output bit BOOL 0.0 to 65535.7 

QB AB Output byte BYTE, CHAR 0 to 65535 

QW AW Output word WORD, INT, S5TIME, DATE 0 to 65534 

QD AD Output double word DWORD, DINT, REAL, TOD, TIME 0 to 65532 

M M Memory bit BOOL 0.0 to 65535.7 

MB MB Memory byte BYTE, CHAR 0 to 65535 

MW MW Memory word WORD, INT, S5TIME, DATE 0 to 65534 

MD MD Memory double word DWORD, DINT, REAL, TOD, TIME 0 to 65532 

PIB PEB Peripheral input byte BYTE, CHAR 0 to 65535 

PQB PAB Peripheral output byte BYTE, CHAR 0 to 65535 

PIW PEW Peripheral input word WORD, INT, S5TIME, DATE 0 to 65534 

PQ PAW Peripheral output word WORD, INT, S5TIME, DATE 0 to 65534 

W 

PID PED Peripheral input double word DWORD, DINT, REAL, TOD, TIME 0 to 65532 

PQD PAD Peripheral output double word DWORD, DINT, REAL, TOD, TIME 0 to 65532 

T T Timer TIMER 0 to 65535 

C Z Counter COUNTER 0 to 65535 

FB FB Function block FB 0 to 65535 

OB OB Organization block OB 1 to 65535 

DB DB Data block DB, FB, SFB, UDT 1 to 65535 

FC FC Function FC 0 to 65535 

SFB SFB System function block SFB 0 to 65535 

SFC SFC System function SFC 0 to 65535 

VAT VAT Variable table 0 to 65535 

UDT UDT User-defined data type UDT 0 to 65535 


A5E00706944-01 8-11


8.5.3 Incomplete and Non-Unique Symbols in the Symbol Table 

Incomplete Symbols 

It is also possible to store incomplete symbols. You can, for example, enter only 

the symbol name first and then add the corresponding address at a later date. This 

means you can interrupt your work on the symbol table at any time, save the 

interim result, and complete your work another time. Incomplete symbols are 

identified in the "Status" column by the symbol. When you come to use the 

symbol for creating software (without an error message appearing), you must have 

entered the symbolic name, the address, and the data type. 

How Ambiguous Symbols Occur 

Ambiguous symbols occur when you insert a symbol in the symbol table whose 

symbolic name and/or address was already used in another symbol row. This 

means both the new symbol and the existing symbol are ambiguous. This status is 

indicated by the symbol 

in the "Status" column. 

This happens, for example, when you copy and paste a symbol in order to change 

the details in the copy slightly. 

Identification of Ambiguous Symbols 

In the symbol table, ambiguous symbols are identified by highlighting them 

graphically (color, font). This change in their representation means they still require 

editing. You can either display all symbols or filter the view so that only unique or 

ambiguous symbols are displayed. 

Making Symbols Unique 

An ambiguous symbol becomes unique when you change the component (symbol 

and/or address) which caused this status. If two symbols are ambiguous and you 

change one of them to make it unique, the other one also becomes unique. 


8-12 A5E00706944-01


8.6 Entering Shared Symbols 

There are three methods of entering symbols that can be used for programming at 

a later stage: 

• Via Dialog Box 

You can open a dialog box in the window where you are entering a program 

and define a new symbol or redefine an existing symbol. This procedure is 

recommended for defining individual symbols, for example, if you realize that a 

symbol is missing or you want to correct one while you are writing the program. 

This saves you displaying the whole symbol table. 

• Directly in the Symbol Table 

You can enter symbols and their absolute addresses directly in a symbol table. 

This procedure is recommended if you want to enter a number of symbols and 

for when you create the symbol table for a project because you have the 

symbols which were already assigned displayed on the screen, making it easier 

to keep an overview of the symbols. 

• Import Symbol Tables from Other Table Editors 

You can create the data for the symbol table in any table editor you are 

comfortable with (for example, Microsoft Excel) and then import the file you 

created into the symbol table. 

8.6.1 General Tips on Entering Symbols 

To enter new symbols in the symbol table, position the cursor in the first empty row 

of the table and fill out the cells. You can insert new rows before the current row in 

the symbol table using the menu command Insert > Symbol. If the row before the 

cursor position already contains an address, you will be supported when inserting 

new symbols by a presetting of the "Address" and "Data Type" columns. The 

address is derived from the previous row; the default data type is entered as data 

type. 

You can copy and modify existing entries using the commands in the Edit menu. 

Save and then close the symbol table. You can also save symbols which have not 

been completely defined. 

When you enter the symbols, you should note the following points: 

Column 

Symbol 

Address 

Data Type 

Note 

The name must be unique within the whole symbol table. When you confirm the entry 

in this field or exit the field, a non-unique symbol is marked. The symbol can contain 

up to 24 characters. Quotation marks (") are not permitted. 

When you confirm the entry in this field or exit the field, a check is made as to whether 

the address entered is allowed. 

When you enter the address, this field is automatically assigned a default data type. If 

you change this default, the program checks whether the new data type matches the 

address. 

Comment You can enter comments here to briefly explain the functions of the symbols (max. 80 

characters). Entering a comment is optional. 


A5E00706944-01 8-13


8.6.2 Entering Single Shared Symbols in a Dialog Box 

The procedure described below shows you how you can change symbols or define 

new symbols in a dialog box while programming blocks without having to display 

the symbol table. 

This procedure is useful if you only want to edit a single symbol. If you want to edit 

a number of symbols, you should open the symbol table and work in it directly. 

Activating Symbol Display in a Block 

You activate the display of symbols in the block window of an open block using the 

menu command View > Display > Symbolic Representation. A check mark is 

displayed in front of the menu command to show that the symbolic representation 

is active. 

Defining Symbols When Entering Programs 

1. Make certain that the symbolic representation is switched on in the block 

window (menu command View > Display > Symbolic Representation.) 

2. Select the absolute address in the code section of your program to which you 

want to assign a symbol. 

3. Select the menu command Edit > Symbol. 

4. Fill out the dialog box and close it, confirming your entries with "OK" and 

making sure you enter a symbol. 

The defined symbol is entered in the symbol table. Any entries that would lead to 

non-unique symbols are rejected with an error message. 

Editing in the Symbol Table 

Using the menu command Options > Symbol Table you can open the symbol 

table to edit it. 


8-14 A5E00706944-01


8.6.3 Entering Multiple Shared Symbols in the Symbol Table 

Opening the Symbol Table 

There are a number of ways of opening a symbol table: 

• Double-click the symbol table in the project window. 

• Select the symbol table in the project window and select the menu command 

Edit > Open Object. 

The symbol table for the active program is displayed in its own window. You can 

now create symbols or edit them. When you open a symbol table for the first time 

after it was created, it is empty. 

Entering Symbols 

To enter new symbols in the symbol table, position the cursor in the first empty row 

of the table and fill out the cells. You can insert new empty rows before the current 

row in the symbol table using the menu command Insert > Symbol. You can copy 

and modify existing entries using the commands in the Edit menu. Save and then 

close the symbol table. You can also save symbols that have not been completely 

defined. 

Sorting Symbols 

The data records in the symbol table can be sorted alphabetically according to 

symbol, address, data type, or comment. 

You can change the way the table is sorted by using the menu command View > 

Sort to open a dialog box and define the sorted view. 

Filtering Symbols 

You can use a filter to select a subset of the records in a symbol table. 

Using the menu command View > Filter you open the "Filter" dialog box. 

You can define criteria which the records must fulfill in order to be included in the 

filtered view. You can filter according to: 

• Symbol names, addresses, data types, comments 

• Symbols with operator control and monitoring attribute, symbols with 

communication properties, symbols for binary variables for messages (bit 

memory or process input) 

• Symbols with the status "valid," "invalid (non-unique, incomplete)" 

The individual criteria are linked by an AND operation. The filtered records start 

with the specified strings. 

If you want to know more about the options in the "Filter" dialog box, open the 

context-sensitive online help by pressing F1. 


A5E00706944-01 8-15


8.6.4 Using Upper and Lower Case for Symbols 

No Distinction between Upper and Lower Case Characters 

Previously it was possible to define symbols in STEP 7 which differed from one 

another only in the case used for individual characters. This was changed in 

STEP 7, V4.02. It is now no longer possible to distinguish between symbols on the 

basis of the case used. 

This change was made in response to the wishes of our customers, and will greatly 

reduce the risk of errors occurring in a program. The restrictions which have been 

made to the symbol definition also support the aims of the PLCopen forum to 

define a standard for transferable programs. 

Symbol definition based solely on a distinction between upper and lower case 

characters is now no longer supported. Previously, for example, the following 

definition was possible in the symbol table: 

Motor1 = I 0.0 

motor1 = I 1.0 

The symbols were distinguished on the basis of the case used for the first letter. 

This type of differentiation carries with it a significant risk of confusion. The new 

definition eliminates this possible source of errors. 

Effects on Existing Programs 

If you have been using this criterion to distinguish between different symbols you 

may experience difficulties with the new definition if: 

• Symbols differ from one another only in their use of upper and lower case 

characters 

• Parameters differ from one another only in their use of upper and lower case 

characters 

• Symbols differ from parameters only in their use of upper and lower case 

characters 

All three of these conflicts can, however, be analyzed and resolved as described 

below. 


8-16 A5E00706944-01


Symbols which Differ from One Another Only in their Use of Upper and Lower 

Case Characters 

Conflict: 

If the symbol table has not yet been edited with the current version of the software, 

the first of the non-unique symbols in the table is used when source files are 

compiled. 

If the symbol table has already been edited, such symbols are invalid; this means 

that the symbols are not displayed when blocks are opened and source files 

containing these symbols can no longer be compiled without errors. 

Remedy: 

Check your symbol table for conflicts by opening the table and saving it again. This 

action enables the non-unique symbols to be recognized. You can then display the 

non-unique symbols using the filter "Non-Unique Symbols" and correct them. You 

should also correct any source files which contain conflicts. You do not need to 

make any further changes to the blocks, as the current (now conflict-free) version 

of the symbol table is automatically used or displayed when a block is opened. 

Parameters which Differ from One Another Only in their Use of Upper and Lower 


Conflict: 

Source files containing such interfaces can no longer be compiled without errors. 

Blocks with such interfaces can be opened, but access to the second of these 

parameters is no longer possible. When you try to access the second parameter, 

the program automatically returns to the first parameter when the block is saved. 

Remedy: 

To check which blocks contain such conflicts, it is advisable to generate a source 

file for all the blocks of a program using the function "Generate Source File." If 

errors occur when you attempt to compile the source file you have created, there 

must be a conflict. 

Correct your source files by ensuring that the parameters are unique; for example, 

by means of the "Find and Replace" function. Then compile the files again. 

Symbols which Differ from Parameters Only in their Use of Upper and Lower 


Conflict: 

If shared and local symbols in a source file only differ from one another in their use 

of upper and lower case characters, and is no initial characters have been used to 

identify shared ("symbol name") or local (#symbol name) symbols, the local symbol 

will always be used during compilation. This results in a modified machine code. 

Remedy: 

In this case it is advisable to generate a new source file from all of the blocks. This 

will automatically assign local and shared access with the corresponding initial 

characters and will ensure that they are handled correctly during future compilation 

procedures. 


A5E00706944-01 8-17


8.6.5 Exporting and Importing Symbol Tables 

You can export the current symbol table to a text file in order to be able to edit it 

with any text editor. 

You can also import tables created using another application into your symbol table 

and continue to edit them there. The import function can be used, for example, to 

include in the symbol table assignment lists created with STEP5/ST following 

conversion. 

The file formats *.SDF, *.ASC, *.DIF, and *.SEQ are available to choose from. 

Rules for Exporting 

You can export the whole symbol table, a filtered subset of the symbol table, or 

rows selected in the table view. 

The properties of symbols that you can set using the menu command Edit > 

Special Object Properties are not exported. 

Rules for Importing 

• For frequently used system function blocks (SFBs), system functions 

(SFCs)and organization blocks (OBs)predefined symbol table entries already 

exist in the file ...\S7DATA\SYMBOL\SYMBOL.SDF which you can import as 

required. 

• The properties of symbols that you can set using the menu command Edit > 

Special Object Properties are not taken into consideration when exporting and 

importing. 

8.6.6 File Formats for Importing/Exporting a Symbol Table 

The following file formats can be imported into or exported out from the symbol 

table: 

• ASCII file format (ASC) 

• Data Interchange Format (DIF) 

You can open, edit, and save DIF files in Microsoft Excel. 

• System Data Format (SDF) 

You can open, edit, and save SDF files in Microsoft Access. 

- To import and export data to and from the Microsoft Access application, 

use the SDF file format. 

- In Access, select the file format "Text (with delimiters)". 

- Use the double inverted comma (") as the text delimiter. 

- Use the comma (,) as the cell delimiter. 

• Assignment list (SEQ) 

Caution: When exporting the symbol table to a file of the type .SEQ comments 

that are longer than 40 characters are truncated after the 40th character. 


8-18 A5E00706944-01


ASCII File Format (ASC) 

File Type *.ASC 

Structure: Record length, delimiter comma, record 

Example: 126,green_phase_ped. T 2 TIMER Duration of green phase for 

pedestrians 

126,red_ped. Q 0.0 BOOL Red for pedestrians 

Data Interchange Format (DIF) 

File Type 

Structure: 

*.DIF 

A DIF file consists of the file header and the data: 

Header TABLE Start of a DIF File 

0,1 

"" 

Comment string 

VECTORS 

Number of records in the file 

0, 

"" 

TUPLES 

Number of data fields in a record 

0, 

"" 

DATA 

ID for the end of the header and start of the data 

0,0 

"" 

Data (per record) , ID for the data type, numeric value 

 

Alphanumeric part or 

V 

if the alphanumeric part is not used 

Header: the file header must contain the record types TABLE, VECTORS, 

TUPLES, and DATA in the order specified. Before DATA, DIF files can contain 

further, optional record types. These are, however, ignored by the Symbol Editor. 

Data: in the data part, each entry consists of three parts: the ID for the Type (data 

type), a numeric value, and an alphanumeric part. 

You can open, edit, and save DIF files in Microsoft Excel. You should not use 

accents, umlauts, or other special language characters. 


A5E00706944-01 8-19


System Data Format (SDF) 

File Type *.SDF 

Structure: Strings in quotation marks, parts separated by commas 

Example: "green_phase_ped.","T 2","TIMER","Duration of green phase for pedestrians" 

"red_ped.","Q 0.0","BOOL","Red for pedestrians" 

To open an SDF file in Microsoft Access you should select the file format 'Text 

(with delimiter)'. Use the double quotation mark (") as the text delimiter and the 

comma (,) as the field delimiter. 

Assignment List (SEQ) 

File Type 

Structure: 

Example: 

*.SEQ 

TAB Address TAB Symbol TAB Comment CR 

T 2 green_phase_ped. Duration of green phase for pedestrians 

Q 0.0 red_ped. Red for pedestrians 

TAB stands for the tabulator key (09H), 

CR stands for carriage return with the RETURN key (0DH). 


8-20 A5E00706944-01


8.6.7 Editing Areas in Symbol Tables 

As of STEP 7 V5.3, you can now select and edit contiguous areas within a symbol 

table. This means that you can copy and/or cut parts of one symbol table and insert 

them into another symbol table or delete them as required. 

This makes it easier to update symbol tables by quickly transferring data from one 

symbol table to another. 

Areas that can be selected: 

• You can select entire rows as soon as you click in the first column in the row. If 

you want to select all the fields, ranging from the "Status" column to the 

"Comments" column, then these are also part of the selected row. 

• You can select one or more contiguous fields as an overall area. To be able to 

select this area, all fields must belong to the "Symbol", "Address", "Data Type" 

and "Comments" columns. If you make an invalid selection, the menu 

commands for editing will not be available. 

• The R, O, M, C, CC columns contain the special object properties for the 

respective symbols and are only copied if the "Also copy special object 

properties" check box is selected in the "Customize" dialog box (menu 

command Options > Customize). 

• The contents of the R, O, M, C, CC columns are copied if these columns are 

displayed. To show or hide these columns, select the View > R, O, M, C, CC 

Columns menu command. 

To edit a symbol table, proceed as follows: 

1. Select the area that you want to edit in the symbol table by using either of the 

following methods: 

- Using the mouse, click in the starting cell, and while keeping the left 

mouse button depressed, move the mouse over the area that you want to 

select. 

- Using the keyboard, select the area by pressing the shift key and then the 

cursor (arrow) keys. 

2. The selected area is shown in reverse video. The cell selected first is shown in 

normal display and is surrounded by a frame. 

3. Edit the area selected as required. 


A5E00706944-01 8-21



8-22 A5E00706944-01

9 Creating Blocks and Libraries 

9.1 Selecting an Editing Method 

Depending on the programming language you use to create a program, you can 

enter your program either in incremental input mode and/or free-edit (text) mode. 

Incremental Editors for the Programming Languages Ladder Logic (LAD), 

Function Block Diagram (FBD), Statement List (STL), or S7-GRAPH 

In the incremental input mode editors for Ladder, FBD, STL, and S7-GRAPH, you 

create blocks that are stored in the user program. You should choose to use 

incremental input mode if you want to check what you have entered immediately. 

This edit mode is particularly suitable for beginners. In incremental input mode, the 

syntax of each line or element is checked immediately after it has been entered. 

Any errors are indicated and must be corrected before completing the entry. 

Entries with correct syntax are automatically compiled and stored in the user 

program. 

Any symbols used must be defined before editing the statements. If certain 

symbols are not available, the block can not be fully compiled; this inconsistent 

interim version can, however, be saved. 

Source Code (Text) Editors for the Programming Languages STL, S7 SCL, or 

S7 HiGraph 

In source code editors, you create source code files for subsequent compilation to 

generate blocks. 

We recommend you use source code editing, as this is a highly efficient program 

editing and monitoring method. 

The source code of the program or block is edited in a text file and then compiled. 

The text files (source files) are stored in the sources folder of your S7 program, for 

example, as an STL source file or SCL source file. A source file can contain code 

for one or multiple blocks. The STL and SCL text editors allow you to generate 

source code for OBs, FBs, FCs, DBs, and UDTs (user-defined data types), 

though you can use them to create a complete user program. One such text file 

may contain the complete program (that is, all blocks) for a CPU. 

When you compile the source file, the corresponding blocks will be generated and 

written to the user program. All symbols used must be defined before you can 

compile them. Data errors are not reported until the respective compiler interprets 

the source file. 

It is imperative for compilation to stay conform with the prescribed syntax of the 

programming language. A syntax check is only performed on account of a user 

instruction or when the source file is compiled into blocks. 


A5E00706944-01 9-1

Creating Blocks and Libraries 

9.2 Selecting the Programming Language 

Setting the Programming Language for the Editor 

Before you you generate a particular block or a source file, select the programming 

language and editor via the object properties. This selection determines which 

editor is started when the block or source file is opened. 

Starting the Editor 

Start the appropriate language editor either in SIMATIC Manager with a doubleclick 

on the corresponding object (block, source file, etc.), by selecting the menu 

command Edit > Open Object or click on the corresponding toolbar button. 

To create an S7 program, the programming languages listed in the table are 

available to you. The STEP 7 programming languages LAD, FBD, and STL are 

supplied with the standard STEP 7 software package. You can purchase other 

programming languages as optional software packages. 

You then have the choice of a number of different programming philosophies 

(Ladder Logic, Function Block Diagram, Statement List, standard language, 

sequential control, or status graph) and whether to use a text-based or a graphic 

programming language. 

Select a programming language to determine the input mode (X). 

Programming 

Language 

Statement List 

STL 

Ladder Logic LAD 

Function Block 

Diagram FBD 

F-LAD, F-FBD 

Optional package 

SCL (Structured 

Control Language) 


S7-GRAPH 

User Group Application Incremental 

Input 

Users who prefer 

programming in a 

language similar to 

machine code 

Users who are 

accustomed to 

working with circuit 

diagrams 

Users who are familiar 

with the logic boxes of 

Boolean algebra 

Users who are familiar 

with the programming 

languages LAD and 

FDB. 

Users who have 

programmed in highlevel 

languages such 

as PASCAL or C 

Users who want to 

work oriented on the 

technological 

functions and do not 

Programs 

optimized in 

terms of run time 

and memory 

requirements 

Programming of 

logic controls 


logic controls 


safety programs 

for F-systems 


data processing 

tasks 

Convenient 

description of 

sequential 

processes 

Free- 

Edit 

Mode 

X X X 

X − X 

X − X 

X − X 

− X − 

X − X 

Block can be 

Documented 

Back from 

the CPU 


9-2 A5E00706944-01



Language 


HiGraph 


CFC 


User Group Application Incremental 

Input 

have extensive 

knowledge of 

programming/PLCs 



technological 

functions and do not 

have extensive 

knowledge of 

programming/PLCs 



technological 

functions without 

extensive 

programming or PLC 

experience 

Convenient 

description of 

asynchronous, 

non-sequential 

processes 

Description of 

continuous 

processes 

Free- 

Edit 

Mode 

− X − 

− − − 

Block can be 

Documented 

Back from 

the CPU 

If blocks contain no errors, you can switch between Ladder Logic, Function Block 

Diagram, or Statement List format. Program parts that cannot be displayed in the 

target language are shown in Statement List format. 

Under STL, you can generate blocks from source files and vice versa. 


A5E00706944-01 9-3


9.2.1 Ladder Logic Programming Language (LAD) 

The graphic programming language Ladder Logic (LAD) is based on the 

representation of circuit diagrams. The elements of a circuit diagram, e.g. normally 

open contacts and normally closed contacts, are combined to form networks. The 

code section of a logic block represents one or more networks. 

Example of Networks in LAD 

 

 

( ) 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

( ) 

 

 

 

( ) 

 

( ) 

 

( ) 

The programming language LAD is supplied with the standard STEP 7 software 

package. Programs are created under LAD with an incremental editor. 


9-4 A5E00706944-01


9.2.2 Function Block Diagram Programming Language (FBD) 

The programming language Function Block Diagram (FBD) is based on graphic 

logic symbols also known in Boolean algebra. Complex functions such as math 

functions can also be displayed directly in combination with the logic boxes. 

The programming language FBD is supplied with the standard STEP 7 software 

package. 

Example of a Network in FBD 

 

 

 

 

 

 

 

 

 

 

 

= 

Programs are created in FBD with an incremental editor. 


A5E00706944-01 9-5


9.2.3 Statement List Programming Language (STL) 

The programming language STL is a text-based programming language with a 

structure similar to machine code. Each statement represents a program 

processing operation of the CPU. Multiple statements can be linked to form 

networks. 

Example of Networks in Statement List 

 

 

 

 

 

 

 

 

 

 

 

 

 

The programming language STL is supplied with the standard STEP 7 software 

package. With this programming language, you can use incremental editors to edit 

S7 blocks and you can create and compile STL program source files in a source 

code editor to generate blocks. 


9-6 A5E00706944-01


9.2.4 S7 SCL Programming Language 

The programming language SCL (Structured Control Language) is available as an 

optional package. This is a high-level text-based language whose global language 

definition conforms to IEC 1131-3. The language closely resembles PASCAL and, 

other than in STL, simplifies the programming of loops and conditional branches 

due to its high-level language commands, for example. SCL is therefore suitable 

for calculating equations, complex optimization algorithms, or the management of 

large data volume. 

S7 SCL programs are written in the source code editor. 

Example: 

FUNCTION_BLOCK FB20 

VAR_INPUT 

ENDVAL: 

INT; 

END_VAR 

VAR_IN_OUT 

IQ1 : 

REAL; 

END_VAR 

VAR 

INDEX: 

INT; 

END_VAR 

BEGIN 

CONTROL:=FALSE; 

FOR INDEX:= 1 TO ENDVALUE DO 

IQ1:= IQ1 * 2; 

IF IQ1 >10000 THEN 

CONTROL = TRUE 

END_IF 

END_FOR; 

END_FUNCTION_BLOCK 


A5E00706944-01 9-7


9.2.5 S7-GRAPH Programming Language (Sequential Control) 

The graphic programming language S7-GRAPH is available as optional package. It 

allows you to program sequential controls. This includes the creation of sequencers 

and the specification of corresponding step contents and transitions. You program 

the contents of the steps in a special programming language (similar to STL). 

Transitions are programmed in a Ladder Logic Editor (a light version of LAD). 

S7-GRAPH displays even complex sequences very clearly and makes 

programming and troubleshooting more effective. 

Example of a Sequential Control in S7-GRAPH 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Blocks Created 

With the S7-GRAPH editor you program the function block that contains the 

sequencer. A corresponding instance DB contains the data for the sequencer, e.g. 

the FB parameters, step and transition conditions. You can generate this instance 

DB automatically in the S7-GRAPH editor. 

Source File 

A text-based source file (GRAPH source file) can be generated from a function 

block created in S7-GRAPH which can be interpreted by OPs or text-based 

displays for displaying the sequencer. 


9-8 A5E00706944-01


9.2.6 S7 HiGraph Programming Language (State Graph) 

The graphic programming language S7 HiGraph is available as an optional 

package. It allows you to program a number of the blocks in your program as 

status graphs. Here you split your system into dedicated functional units which can 

acquire different states and you define the transition conditions between states. 

You describe the actions assigned to the states and the conditions for the 

transitions between the states in a zoom-type language similar to Statement List. 

You create a graph for each functional unit that describes the response of this 

functional unit. The plant graphs are gathered in graph groups. The graphs can 

communicate to synchronize functional units. 

The well arranged view of the status transitions of a functional unit allows 

systematic programming and simplifies debugging. The difference between 

S7-GRAPH and S7-HiGraph is, that the latter acquires only one state (in 

S7-GRAPH: "step") at any one time. The figure below shows how to create graphs 

for functional units (example). 


A5E00706944-01 9-9


A graph group is stored in a HiGraph source file in the "Source" folder of the S7 

program. This source file is then compiled to generate S7 blocks for the user 

program. 

Syntax and formal parameters are checked after the last entry was made in a 

graph (when the working window is closed). Addresses and symbols are not 

checked until the source file is being compiled. 

9.2.7 S7 CFC Programming Language 

The optional software package CFC (Continuous Function Chart) is a programming 

language used to link complex functions graphically. 

You use the programming language S7 CFC to link existing functions. You do not 

need to program many standard functions yourself, instead you can use libraries 

containing standard blocks (for example, for logic, math, control, and data 

processing functions). To use CFC you do not require any detailed programming 

knowledge or specific knowledge of programmable control, and you can 

concentrate on the technology used in your branch of industry. 

The program created is stored in the form of CFC charts. These are stored in the 

"Charts" folder beneath the S7 program. These charts are then compiled to form 

the S7 blocks for the user program. 

You may want to create blocks to be connected yourself, in which case you 

program them for SIMATIC S7 with one of the S7 programming languages, and for 

SIMATIC M7 with C/C++. 


9-10 A5E00706944-01


9.3 Creating Blocks 

9.3.1 Blocks Folder 

You can create the program for an S7 CPU in the form of: 

• Blocks 

• Source files 

The folder "Blocks" is available under the S7 program for storing blocks. 

This block folder contains the blocks you need to download to the S7 CPU for your 

automation task. These loadable blocks include logic blocks (OBs, FBs, FCs) and 

data blocks (DB). An empty organization block OB1 is automatically created with 

the block folder because you will always need this block to execute your program in 

the S7 CPU. 

The block folder also contains the following objects: 

• The user-defined data types (UDT) you created. These make programming 

easier but are not downloaded to the CPU. 

• The variable tables (VAT) that you can create to monitor and modify variables 

for debugging your program. Variable tables are not downloaded to the CPU. 

• The object "System Data" (system data blocks) that contains the system 

information (system configuration, system parameters). These system data 

blocks are created and supplied with data when you configure the hardware. 

• The system functions (SFC) and system function blocks (SFB) that you need to 

call in your user program. You cannot edit the SFCs and SFBs yourself. 

With the exception of the system data blocks (which can only be created and 

edited via the configuration of the programmable logic controller), the blocks in the 

user program are all edited using the respective editor. This editor is started 

automatically by double-clicking the respective block. 

Note 

The blocks you programmed as source files and then compiled are also stored in 

the block folder. 


A5E00706944-01 9-11


9.3.2 User-Defined Data Types (UDT) 

User-defined data types are special data structures you create yourself that you 

can use in the whole S7 program once they have been defined. 

• User-defined data types can be used like elementary data types or complex 

data types in the variable declaration of logic blocks (FC, FB, OB) or as a data 

type for variables in a data block (DB). You then have the advantage that you 

only need to define a special data structure once to be able to use it as many 

times as you wish and assign it any number of variables. 

• User-defined data types can be used as a template for creating data blocks with 

the same data structure, meaning you create the structure once and then create 

the required data blocks by simply assigning the user-defined data type 

(Example: Recipes: The structure of the data block is always the same, only the 

amounts used are different.) 

User-defined data types are created in the SIMATIC Manager or the incremental 

editor − just like other blocks. 

Structure of a User-Defined Data Type 

When you open a user-defined data type, a new working window is displayed 

showing the declaration view of this user-defined data type in table form. 

• The first and the last row already contain the declarations STRUCT and 

END_STRUCT for the start and the end of the user-defined data type. You 

cannot edit these rows. 

• You edit the user-defined data type by typing your entries in from the second 

row of the declaration table in the respective columns. 

• You can structure user-defined data types from: 

- Elementary data types 

- Complex data types 

- Existing user-defined data types 

The user-defined data types in the S7 user program are not downloaded to the S7 

CPU. They are either created directly using an incremental input editor and edited, 

or they are created when source files are compiled. 


9-12 A5E00706944-01


9.3.3 Block Properties 

You can more easily identify the blocks you created if you use block properties and 

you can also protect these blocks from unauthorized changes. 

You should edit the block properties when the block is open. In addition to the 

properties you can edit, the properties dialog box also displays data for your 

information only: you cannot edit this information. 

The block properties and system attributes are also displayed in the SIMATIC 

Manager in the object properties for a block. Here you can only edit the properties 

NAME, FAMILY, AUTHOR, and VERSION. 

You edit the object properties after you insert the block via the SIMATIC Manager. 

If a block was created using one of the editors and not in the SIMATIC Manager, 

these entries (programming language) are saved automatically in the object 

properties. 

Note 

The mnemonics you want to use to program your S7 blocks can be set in the 

SIMATIC Manager using the menu command Options > Customize and the 

"Language" tab. 

Table of Block Properties 

When entering block properties, you should observe the input sequence shown in 

the following table: 

Keyword / Property Meaning Example 

[KNOW_HOW_PROTECT] Block protection; a block compiled with KNOW_HOW_PROTECT 

this option does not allow its code 

section to be viewed. The interface for 

the block can be viewed, but it cannot be 

changed. 

[AUTHOR:] 

Name of author: company name, 

department name, or other name 

(max. 8 characters without blanks) 

AUTHOR : Siemens, but no 

keyword 

[FAMILY:] 

Name of block family: for example, 

controllers 


FAMILY : controllers, but no 

keyword 

[NAME:] Block name (max. 8 characters) NAME : PID, but no keyword 

[VERSION: int1 . int2] Version number of block 

VERSION : 3.10 

(both numbers between 0 and 15, 

meaning 0.0 to 15.15) 

[CODE_VERSION1] ID whether a function block can have 

multiple instances declared or not. If you 

want to declare multiple instances, the 

function block should not have this 

property 

CODE_VERSION1 


A5E00706944-01 9-13


Keyword / Property Meaning Example 

[UNLINKED] for DBs only! 

[Non-Retain] 

[READ_ONLY] for DBs 

only 

Read-only block 

Data blocks with the UNLINKED 

property are only stored in the load 

memory. They take up no space in the 

working memory and are not linked to 

the program. They cannot be accessed 

with MC7 commands. Depending on the 

specific CPU, the contents of such a DB 

can be transferred to the working 

memory only with SFC 20 BLKMOV or 

SFC 83 READ_DBL. 

Data blocks with this attribute are reset 

to the load values after every power OFF 

and power ON and after every STOP- 

RUN transition of the CPU. 

Write protection for data blocks; its data 

can only be read and cannot be 

changed 

A copy of a block that is stored in readonly 

status for reference purposes. This 

property can only be assigned in the 

program editor by selecting File > Store 

Read-Only menu command. 

READ_ONLY 

The block protection KNOW_HOW_PROTECT has the following consequences: 

• If you want to view a compiled block at a later stage in the incremental STL, 

FBD, or Ladder editors, the code section of the block cannot be displayed. 

• The variable declaration table for the block displays only the variables of the 

declaration types var_in, var_out, and var_in_out. The variables of the 

declaration types var_stat and var_temp remain hidden. 

Assignment: Block Property to Block Type 

The following table shows which block properties can be declared for which block 

types: 

Property OB FB FC DB UDT 

KNOW_HOW_PROTECT • • • • − 

AUTHOR • • • • − 

FAMILY • • • • − 

NAME • • • • − 

VERSION • • • • − 

UNLINKED − − − • − 

READ_ONLY − − − • − 

Non-Retain − − − • − 

Read-only block • • • • • 

The KNOW_HOW_PROTECT property can be set in a source file when you 

program the block. It is displayed in the "Block Properties" dialog box but cannot be 

changed. 


9-14 A5E00706944-01


9.3.4 Displaying Block Lengths 

Block lengths are displayed in "bytes." 

Display in the Block Folder Properties 

The following lengths are displayed in the block folder properties in the offline view: 

• Size (sum of all blocks without system data) in the load memory of the 

programmable controller 

• Size (sum of all blocks without system data) in the work memory of the 


• Block lengths on the programming device (PG/PC) are not displayed in the 

block folder properties. 

Display in the Block Properties 

The following are displayed in the block properties: 

• Required number of local data: size of the local data in bytes 

• MC7: size of the MC7 code in bytes, or size of the DB user data 

• Size of the load memory in the programmable controller 

• Size of the work memory in the programmable controller: only displayed if 

hardware assignment is recognized. 

For display purposes, it does not matter whether the block is located in the window 

of an online view or an offline view. 

Display in the SIMATIC Manager (Details View) 

If a block folder is opened and the "Details View" selected, the work memory 

requirement is displayed in the project window, irrespective of whether the block 

folder is located in the window of an online view or an offline view. 

You can calculate the sum of the block lengths by selecting all the relevant blocks. 

In this case, the sum of the selected blocks is displayed in the status bar of the 


No lengths are displayed for blocks which cannot be downloaded to the 

programmable controller (for example, variable tables). 

Block lengths on the programming device (PG/PC) are not displayed in the Details 

view. 


A5E00706944-01 9-15


9.3.5 Comparing Blocks 

Introduction 

To compare blocks that are in different locations, you can start the block 

comparison process in either of the following ways: 

• Go to the SIMATIC Manager and select the Options > Compare Blocks menu 

command. In the "Compare Blocks - Results" dialog box that is displayed, click 

the "Go to" button. The results of the comparison will appear in the program 

editor (LAD/FBD/STL) in the "Comparison" tab 

• Go to the program editor. Select the Options > Compare On-/Offline Partners 

menu command. 

The following sections explain how the block-comparison process functions. In the 

following discussion, a distinction is maintained between logic blocks (OBs, FBs, 

FCs) and data blocks (DBs). 

How Block Comparison Works: Logic Blocks 

In the first step of the process, STEP 7 compares the time stamps for the interfaces 

of the logic blocks to be compared. If these time stamps are identical, STEP 7 

assumes that the interfaces are identical. 

If the time stamps are different, STEP 7 then compares the data types in the 

interfaces step-by-step by section. When a difference is found, STEP 7 determines 

the first difference in a section; that is, in each case the first difference in the 

respective declaration ranges. Multi-instances and UDTs are also included in the 

comparison. If the data types in the sections are the same, STEP 7 then compares 

the initial values of the variables. All differences are displayed. 

In the second step, STEP 7 checks the code by network by network (in case the 

"Execute code comparison" option was not selected, the code will still be compared 

if the "Go to" button in the Program Editor is clicked.). 

First, the inserted or deleted networks are detected. The results of the comparison 

will show networks that are only present in one block. These will have the comment 

"only in". 

Then, the remaining networks are compared until the first difference in statements 

is found. Statements are compared in the following manner: 

• For the setting "Absolute address has priority", based on the absolute address 

• For the setting "Symbol has priority", based on the symbol 

Statements are considered to identical if their operators and addresses are the 

same. 

If the blocks to be compared were programmed in different programming 

languages, STEP 7 performs the comparison based on the STL language. 

Special feature of offline-offline comparisons: 

In contrast to an offline-online comparison, in an offline-offline comparison, 

STEP 7also detects the presence of different variable names. This additional step 

is not possible for an offline-offline comparison since only replacement symbols are 

available online. 

Comments for block networks and lines as well as other block attributes (such as 

S7-PDIAG information and messages) are excluded from comparisons. 


9-16 A5E00706944-01


How Block Comparison Works: Data Blocks 


of the data blocks to be compared (as for logic blocks). If these time stamps are 

identical, STEP 7 assumes that the data structures are identical. 

If the interface time stamps are different, STEP 7 then compares the data 

structures until the first difference is found. If the data structures are in the sections 

are identical, STEP 7 then compares the initial values and current values. All 

differences are displayed. 

Special feature of offline-offline comparisons: 

In contrast to an offline-online comparison, in an offline-offline comparison, STEP 7 

also detects the presence of different variable names. This additional step is not 

possible for an offline-offline comparison since only replacement symbols are 

available online. 

Comments and structures for UDTs that are used in a data block are excluded from 

comparisons. 

How Block Comparison Works: Data Types (UDT) 


of the data types to be compared (as for data blocks). If these time stamps are 

identical, STEP 7 assumes that the data structures are identical. 

If the interface time stamps are different, STEP 7 then compares the data 

structures until the first difference is found. If the data structures are in the sections 

are identical, STEP 7 then compares the initial values. All differences are 

displayed. 

How Block Comparison Works: Comparison in the Program Editor 

1. Open the block to be compared to the loaded version. 

2. Select the Options > Compare On-/Offline Partners menu command. 

If the online partner is accessible, then the results of the comparisons will be 

displayed in the lower section of the program editor window in the 

"7:Comparison" tab. 

Tip: If two networks are determined to be "different", then you can open the 

relevant network simply by double-clicking in its row. 


A5E00706944-01 9-17


How Block Comparison Works: Comparison in the SIMATIC Manager 

1. In the SIMATIC Manager, select the block folder or the blocks to be compared. 

2. Select the Options > Compare Blocks menu command. 

3. In the "Compare Blocks" dialog box that is displayed, select the type of 

comparison (ONLINE/offline or Path1/Path2). 

4. For a Path1/Path2 comparison: In the SIMATIC Manager, select the block 

folder or the blocks to be compared. These blocks are then automatically 

entered in the dialog box. 

5. If also want to compare SDBs, select the "Including SDBs" check box. 

6. If you also want to compare code, select the "Execute code comparison" check 

box. In a detailed comparison, in addition to the execution-related parts of the 

block (interface and code), any changes in the names for local variables and 

parameters are displayed. In addition, you can select the "Including blocks 

created in different programming languages" check box to compare blocks 

created in different programming languages (e.g. AWL, FUP....). In this case, 

the blocks are compared based on STL. 

7. Confirm your settings in the dialog box by clicking "OK". 

The results of the comparison are displayed in the "Compare Blocks - Results" 

dialog box. 

To display the properties (i.e. time of last modification, checksum, etc.) of the 

compared blocks, click on the "Details" button in this dialog box 

To open the program editor, in which the results of the comparison are 

displayed in the lower portion of the window, click the "Go to" button. 

Note 

When comparing an offline block folder with an online one, only loadable block 

types (OB, FB, ...) are compared. 

When comparing offline/online or Path1/Path2, all blocks included in a multiple 

selection are compared, even if some of then are not loadable ones (i.e. variable 

tables or UDTs). 


9-18 A5E00706944-01


9.3.6 Rewiring 

The following blocks and addresses can be rewired: 

• Inputs, outputs 

• Memory bits, timers, counters 

• Functions, function blocks 

To rewire: 

1. Select the "Blocks" folder that contains the individual blocks you want to rewire 

in the SIMATIC Manager. 

2. Select the menu command Options > Rewire. 

3. Enter the required replacements (old address/new address) in the table in the 

"Rewire" dialog box. 

4. Select the option "All addresses within the specified address area" if you want 

to rewire address areas (BYTE, WORD, DWORD). 

Example: You enter IW0 and IW4 as the address areas. The addresses I0.0 – 

I1.7 are then rewired to the addresses I4.0 – I5.7. Addresses from the rewired 

area (for example, I0.1) can then no longer be entered in the table individually. 

5. Click the "OK" button. 

This starts the rewire process. After rewiring is completed, you can specify in a 

dialog box whether you want to see the info file on rewiring. This info file contains 

the address lists "Old address" and "New address." The individual blocks are listed 

with the number of wiring processes that have been carried out in each one. 

When rewiring, the following should be noted: 

• When you rewire (that is, rename) a block, the new block cannot currently exist. 

If the block exists, the process is interrupted. 

• When you rewire a function block (FB), the instance data block is automatically 

assigned to the rewired FB. The instance DB does not change, that is, the DB 

number is retained. 

9.3.7 Attributes for Blocks and Parameters 

A description of the attributes can be found in the reference help on system 

attributes: 

• Jumps to Language Descriptions and Help on Blocks and System Attributes 


A5E00706944-01 9-19


9.4 Working with Libraries 

Libraries serve to store reusable program components for SIMATIC S7/M7. The 

program components can be copied to the library from existing projects or created 

directly in the library independently of other projects. 

You can save yourself a lot of programming time and effort if you store blocks 

which you want to use many times in a library in an S7 program. You can copy 

them from there to the user program where they are required. 

To create S7/M7 programs in a library, the same functions apply as for projects – 

with the exception of debugging. 

Creating Libraries 

You can create libraries just like projects using the menu command File > New. 

The new library is created in the directory you set for libraries in the "General" tab 

when you selected the menu command Options > Customize. 

Note 

The SIMATIC Manager allows names that are longer than eight characters. The 

name of the library directory is, however, cut off to eight characters. Library names 

must therefore differ in their first eight characters. The names are not casesensitive. 

When this directory is opened in the Browser, the full name is displayed 

again, but when browsing for the directory, only the shortened name appears. 

Note that you cannot use blocks from libraries of a new STEP 7 version in 

projects of an older STEP 7 version. 

Opening Libraries 

To open an existing library, enter the menu command File > Open. Then select a 

library in the dialog boxes that follow. The library window is then opened. 

Note 

If you cannot find the library you require in the library list, click the "Browse" button 

in the "Open" dialog box. The standard Windows browser then displays the 

directory structure in which you can search for the library. 

Note that the name of the file always corresponds to the original name of the 

library when it was created, meaning any name changes made in the SIMATIC 

Manager are not made at file level. 

When you select a library it is added to the library list. You can change the entries 

in the library list using the menu command File > Manage. 


9-20 A5E00706944-01


Copying Libraries 

You copy a library by saving it under another name using the menu command File 

> Save As. 

You copy parts of a library such as programs, blocks, source files etc. using the 

menu command Edit > Copy. 

Deleting a Library 

You delete a library using the menu command File > Delete. 

You delete parts of a library such as programs, blocks, source files etc. using the 

menu command Edit > Delete. 


A5E00706944-01 9-21


9.4.1 Hierarchical Structure of Libraries 

Libraries are structured in a hierarchical manner, just like projects: 

• Libraries can contain S7/M7 programs. 

• An S7 program can contain one "Blocks" folder (user program), one "Source 

Files" folder, one "Charts" folder, and one "Symbols" object (symbol table). 

• An M7 program can contain charts and C programs for programmable M7 

modules as well as a "Symbols" object (symbol table) and a "Blocks" folder for 

data blocks and variable tables. 

• The "Blocks" folder contains the blocks that can be downloaded to the S7 CPU. 

The variable tables (VAT) and user-defined data types in the folder are not 

downloaded to the CPU. 

• The "Source Files" folder contains the source files for the programs created in 

the various programming languages. 

• The "Charts" folder contains the CFC charts (only if the S7 CFC optional 

software is installed). 

When you insert a new S7/M7 program, a "Blocks" folder, "Source Files" folder (S7 

only), and a "Symbols" object are inserted automatically in it. 

9.4.2 Overview of the Standard Libraries 

The STEP 7 standard software package contains the following standard libraries 

• System Function Blocks: System Function Blocks (SFBs) and System 

Functions (SFCs) 

• S5-S7 Converting Blocks: Blocks for converting STEP 5 programs 

• IEC Function Blocks: Blocks for IEC functions, e.g. for processing time and 

date information, comparison operations, string processing and selecting the 

min./max. values 

• Organization Blocks: Default organization blocks (OB)s 

• PID Control Blocks: Function Blocks (FBs) for PID control 

• Communication Blocks: Functions (FCs) and function blocks for 

SIMATICNET CPs. 

• TI-S7 Converting Blocks: Standard functions for general use 

• Miscellaneous Blocks: Blocks for time stamping and for TOD synchronization 

When you install optional software packages, other libraries may be added. 


9-22 A5E00706944-01


Deleting and Installing the Supplied Libraries 

You can delete the supplied libraries in SIMATIC Manager and then reinstall them. 

Run STPE 7 Setup to install the libraries.. 

Note 

When you install STEP 7, the supplied libraries are always copied. If you edit 

these libraries, the modified libraries will be overwritten with the originals when 

STEP 7 is installed again. 

For this reason, you should copy the supplied libraries before making any 

changes and then only edit the copies. 


A5E00706944-01 9-23



9-24 A5E00706944-01

10 Creating Logic Blocks 

10.1 Basics of Creating Logic Blocks 

10.1.1 Structure of the Program Editor Window 

The window of the program editor is split into the following areas: 

Tables 

The "Program Elements" tab displays a table of the program elements you can 

insert into your LAD, FBD or STL program. The "Call Structure" tab shows the call 

hierarchy of the blocks in the current S7 program. 

Variable Declaration 

The variable declaration is split in to the sections "Variable Table" and "Variable 

Detail View". 

Instructions 

The instruction list shows the block code that is to be processed by the PLC. It 

consists of one or several networks. 


A5E00706944-01 10-1

Creating Logic Blocks 

Details 

The various tabs in the "Details" window provide functions, for example, for 

displaying error messages, editing symbols, providing address information, 

controlling addresses, comparing blocks and for editing error definitions for 

hardware diagnostics. 


10-2 A5E00706944-01


10.1.2 Basic Procedure for Creating Logic Blocks 

Logic blocks (OBs, FBs, FCs) consist of a variable declaration section, a code 

section as well as their properties. When programming, you must edit the following 

three parts: 

• Variable declaration: In the variable declaration you specify the parameters, 

system attributes for parameters, and local block-specific variables. 

• Code section: In the code section you program the block code to be processed 

by the programmable controller. This consists of one or more networks. To 

create networks you can use, for example, the programming languages Ladder 

Logic (LAD), Function Block Diagram (FBD), or Statement List (STL). 

• Block properties: The block properties contain additional information such as a 

time stamp or path that is entered by the system. In addition, you can enter your 

own details such as name, family, version, and author and you can assign 

system attributes for blocks. 

In principle it does not matter in which order you edit the parts of a logic block. You 

can, of course, also correct them and add to them. 

 

 

 

 

 

 

 

 

 

 

Note 

If you want to make use of symbols in the symbol table, you should first check that 

they are complete and make any necessary corrections. 


A5E00706944-01 10-3


10.1.3 Default Settings for the LAD/STL/FBD Program Editor 

Before you start programming, you should make yourself familiar with the settings 

in the editor in order to make it easier and more comfortable for you when 

programming. 

Using the menu command Options > Customize you open a tabbed dialog box. In 

the various tabs you can make the following default settings for programming 

blocks, e.g. in the "General" tab: 

• The fonts (type and size) for text and tables. 

• Whether you want symbols and comments to be displayed with a new block. 

You can change the settings for language, comments, and symbols during editing 

using the commands in the View >… menu. 

You can change the colors used for highlighting, for example, networks or 

statement lines in the "LAD/FBD" tab. 

10.1.4 Access Rights to Blocks and Source Files 

When editing a project, a common database is often used, meaning that a number 

of personnel may want to access the same block or data source at the same time. 

The read/write access rights are assigned as follows: 

• Offline editing: 

When you attempt to open a block/source file, a check is made to see whether 

you have 'write' access to the object. If the block/source file is already open, you 

can only work with a copy. If you then attempt to save the copy, the system 

queries whether you want to overwrite the original or save the copy under a new 

name. 

• Online editing: 

When you open an online block via a configured connection, the corresponding 

offline block is disabled, preventing it from being edited simultaneously. 


10-4 A5E00706944-01


10.1.5 Instructions from the Program Elements Table 

The "Program elements" tab in the overview window provides LAD and FBD 

elements as well as already declared multiple instances, pre-configured blocks and 

blocks from libraries. You can access the tab via menu command View > Tables. 

You can also insert program elements in the code section using the menu 

command Insert > Program Elements. 

Example of the "Program Elements" Tab in LAD 


A5E00706944-01 10-5


10.2 Editing the Variable Declaration 

10.2.1 Using the Variable Declaration in Logic Blocks 

After you open a logic block, a window opens that contains in the upper section the 

variable table and the variable detail view for the block as well as the instruction list 

in the lower section in which you edit the actual block code. 

Example: Variable Views and Instruction List in STL 


10-6 A5E00706944-01


In the variable detail view, you specify the local variables and the formal 

parameters for the block as well as the system attributes for parameters. This has 

the following effects: 

• During declaration, sufficient memory space is reserved for temporary variables 

in the local data stack, and in the case of function blocks, for static variables in 

the instance DB to be associated later. 

• When setting input, output, and in/out parameters you also specify the 

"interface" for the call of a block in the program. 

• When you declare the variables in a function block, these variables (with the 

exception of the temporary variables) also determine the data structure for 

every instance DB that is associated with the function block. 

• By setting system attributes you assign special properties, for example, for the 

configuration of message and connection functions, for operator control and 

monitoring functions and the process control configuration. 


A5E00706944-01 10-7


10.2.2 Interaction Between The Variable Detail View And The 

Instruction List 

The variable declaration and instruction list of logic blocks are closely related, 

because for programming the names specified in the variable declaration are used 

in the instruction list. All changes in the variable declaration will therefore influence 

the entire instruction list. 

Action in the Variable Declaration 

Correct new entry 

Correct name change without type change 

Correct name is changed to an invalid name 

Invalid name is changed to a correct name 

Type change 

Deleting a variable (symbolic name) used in the 

code 

Reaction in the Code Section 

If invalid code present, previously undeclared 

variable now becomes valid 

Symbol is immediately shown everywhere with its 

new name 

Code remains unchanged 

If invalid code is present, it becomes valid 

If invalid code is present, it becomes valid and if 

valid code is present, this may become invalid 

Valid code becomes invalid 

Change to comments, faulty input of a new variable, change to an initial value, or 

deleting an unused variable has no effect on the instruction list. 


10-8 A5E00706944-01


10.2.3 Structure of the Variable Declaration Window 

The variable declaration window consists of the overview of variables and of the 

variable detail view. 

After you have generated and opened a new code block, a default variable table is 

displayed. It lists only the declaration types (in, out, in_out, stat, temp) permitted for 

the selected block, namely in the prescribed order. You can edit the default 

variable declaration that is displayed after you have generated a new OB. 

Permitted data types of local data for the various block types are found under 

Assigning the Data Typs To Local Data Of Code Blocks. 


A5E00706944-01 10-9


10.3 Multiple Instances in the Variable Declaration 

10.3.1 Using Multiple Instances 

It is possible that you may want to or have to use a restricted number of data 

blocks for instance data owing to the performance (for example, memory capacity) 

of the S7 CPUs you are using. If other existing function blocks are called in an FB 

in your user program (call hierarchy of FBs), you can call these other function 

blocks without their own (additional) instance data blocks. 

Use the following solution: 

• Include the function blocks you want to call as static variables in the variable 

declaration of the calling function block. 

• In this function block, call other function blocks without their own (additional) 

instance data blocks. 

• This concentrates the instance data in one instance data block, meaning you 

can use the available number of data blocks more effectively. 

The following example illustrates the solution described: FB2 and FB3 use the 

instance DB of the function block FB1 from which they were called. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Only requirement: You must "tell" the calling function block which instances you are 

calling and what (FB) type these instances are. These details must be entered in 

the declaration window of the calling function block. The function block used must 

have at least one variable or parameter from the data area (VAR_TEMP cannot be 

used). 

Do not use multiple instance data blocks if online changes are expected while the 

CPU is running. Surge-free reloading is only guaranteed when using instance data 

blocks. 


10-10 A5E00706944-01


10.3.2 Rules for Declaring Multiple Instances 

The following rules apply to the declaration of multiple instances: 

• Declaring multiple instances is only possible in function blocks that were 

created with STEP 7 from Version 2 onwards (see Block Attribute in the 

properties of the function block). 

• In order to declare multiple instances, the function block must be created as a 

function block with multiple instance capability (default setting from STEP 7 

Version x.x; can be deactivated in the editor using Options > Customize). 

• An instance data block must be assigned to the function block in which a 

multiple instance is declared. 

• A multiple instance can only be declared as a static variable (declaration type 

"stat"). 

Note 

• You can also create multiple instances for system function blocks. 

• If the function block was not created as being able to have multiple instances 

and you want it to have this property, you can generate a source file from the 

function block in which you then delete the block property CODE_VERSION1 

and then compile the function block again. 

10.3.3 Entering a Multiple Instance in the Variable Declaration Window 

1. Open the function block from which the subordinate function blocks are to be 

called. 

2. Define a static variable in the variable declaration of the calling function block 

for each call of a function block for whose instance you do not want to use an 

instance data block. 

- In the variable table, select hierarchy level "STAT". 

- Enter a name for the FB call in the "Name" column of the variable detail 

view 

- Enter the function block you want to call in the "Data type" column as an 

absolute address or with its symbolic name. 

- You can enter any explanations required in the comment column. 

Calls in the Code Section 

When you have declared multiple instances, you can use FB calls without 

specifying an instance DB. 

Example: If the static variable "Name: Motor_1 , Data type: FB20" is defined, the 

instance can be called as follows: 

Call Motor_1 

// Call of FB20 without instance DB 


A5E00706944-01 10-11


10.4 General Notes on Entering Statements and Comments 

10.4.1 Structure of the Code Section 

In the code section you program the sequence for your logic block by entering the 

appropriate statements in networks, depending on the programming language 

chosen. After a statement is entered, the editor runs an immediate syntax check 

and displays any errors in red and italics. 

The code section for a logic block generally comprises a number of networks that 

are made up of a list of statements. 

In a code section you can edit the block title, block comments, network title, 

network comments, and statement lines within the networks. 

Structure of the Code Section Using the STL Programming Language as an 

Example 


10-12 A5E00706944-01


10.4.2 Procedure for Entering Statements 

You can edit the parts of the code section in any order. We recommend you 

proceed as follows when you program a block for the first time: 

 

 

 

 

 

 

 

You can make changes in either overwrite mode or insert mode. You switch 

between modes using the INSERT key. 


A5E00706944-01 10-13


10.4.3 Entering Shared Symbols in a Program 

Using the menu command Insert > Symbol you can insert symbols in the code 

section of your program. If the cursor is positioned at the beginning, the end, or 

within a string, the symbol is already selected that starts with this string - if such a 

symbol exists. If you change the string, the selection is updated in the list. 

Separators for the beginning and end of a string are, for example, blank, period, 

colon. No separators are interpreted within shared symbols. 

To enter symbols, proceed as follows: 

1. Enter the first letter of the required symbol in the program. 

2. Press CTRL and J simultaneously to display a list of symbols. The first symbol 

starting with the letter you entered is already selected. 

3. Enter the symbol by pressing RETURN or select another symbol. 

The symbol enclosed in quotation marks is then entered instead of the first letter. 

In general the following applies: if the cursor is located at the beginning, the end, or 

within a string, this string is replaced by the symbol enclosed in quotation marks 

when inserting a symbol. 


10-14 A5E00706944-01


10.4.4 Title and Comments for Blocks and Networks 

Comments make your user program easier to read and therefore make 

commissioning and troubleshooting easier and more effective. They are an 

important part of the program documentation and should certainly be made use of. 

Comments in LAD, FBD and STL Programs 

The following comments are available: 

• Block title: title for a block (max. 64 characters) 

• Block comment: documents the whole logic block, for example, the purpose of 

the block 

• Network title: title for a network (max. 64 characters) 

• Network comment: documents the functions of a single network 

• Comment column in the variable detail view: comments the declared local data 

• Symbol comment: comments that were entered for an address when its 

symbolic name was defined in the symbol table. 

You can display these comments using the menu command View > Display 

with > Symbol Information. 

In the code section of a logic block you can enter the block title and network title, 

and block comments or network comments. 

Block Title or Network Title 

To enter a block or network title, position the cursor on the word "Title" to the right 

of the block name or network name (for example, Network 1: Title:). A text box is 

opened in which you can enter the title. This can be up to 64 characters long. 

Block comments pertain to the whole logic block. There they can comment the 

function of the block. Network comments pertain to the individual networks and 

document details about the network. 

 

 

 

 

 

 

To assign network titles automatically, select menu command Options > Settings 

and click on the option "Automatic Assignment of Network Title" in the "General" 

tab. The symbol comment of the first address entered will then be applied as 

network title. 


A5E00706944-01 10-15


Block Comments and Network Comments 

You can toggle the view of the gray comment fields on and off using the menu 

command View > Display with > Comments. A double-click on the comment field 

opens the text box in which you can now enter your remarks. You are allowed 64 

Kbytes per block for block comments and network comments. 

 

 

 

 

10.4.5 Entering Block Comments and Network Comments 

1. Activate the comments with the menu command View > Display with > 

Comments (a check mark is visible in front of the menu command). 

2. Position the cursor in the gray field below the block name or below the network 

name by clicking with the mouse. The gray comment field appears white and 

has a border. 

3. Enter your comment in the open text box. You are allowed 64 Kbytes per block 

for block comments and network comments. 

4. Exit the text box by clicking with the mouse outside the text box, by pressing 

the TAB key, or using the key combination SHIFT+TAB. 

5. If you select the menu command View > Display with > Comments again, 

you can switch off the comments again (the check mark disappears). 


10-16 A5E00706944-01


10.4.6 Working with Network Templates 

When programming blocks, if you would like to use networks multiple times, you 

can store these networks in a library as network templates, complete with 

wildcards, if appropriate (for example, for addresses). The library must be available 

before you create the network template. 

Creating a Network Template 

Create a new library in the SIMATIC Manager if necessary. Select the menu 

command Insert > Program > S7 Program to insert a program into the library. 

1. Open the block that contains the network(s) from which you want to create a 

network template. 

2. In the opened block, replace the title, comment, or addresses with wildcards as 

required. You can use the strings %00 to %99 as wildcards. Wildcards for 

addresses are displayed in red. This is not a problem here because you will not 

be saving the block after you create the network template. You can replace the 

wildcards later with appropriate addresses when you insert the network 

template into a block. 

3. Select "Network " of the network(s) you want to include in the network 

template. 

4. Select the menu command Edit > Create Network Template. 

5. Enter a meaningful comment for each wildcard used in the dialog box 

displayed. 


7. Select the source file folder of the S7 program in your network template 

library in the browser that appears and enter a name for the network template. 

8. Confirm your entry by clicking the "OK" button. The network template is stored 

in the selected library. 

9. Close the block without saving it. 

Inserting a Network Template in a Program 

1. Open the block in which you want to insert the new network. 

2. In the opened block, click in the network after which you want to insert a new 

network based on the network template. 

3. Open the "Program Elements" tab (menu command Insert > Program 

Elements). 

4. Open the "S7 Program" folder of the relevant library in the catalog. 

5. Double-click the network template. 

6. In the dialog box, enter the required replacements for the wildcards in the 

network template. 

7. Click the "OK" button. The network template is then inserted after the current 

network. 

Note 

You can also drag and drop the template from the tab to the editor window. 


A5E00706944-01 10-17


10.4.7 Search Function for Errors in the Code Section 

Errors in the code section are easy to recognize by their red color. To make it 

easier to navigate to errors that lie outside the visible area on the screen, the editor 

offers two search functions Edit > Go To > Previous Error/Next Error. 

The search for errors goes beyond one network. This means that the whole code 

section is searched and not just one network or the area currently visible on the 

screen. 

If you activate the status bar using the menu command View > Status Bar, notes 

on the errors found are displayed there. 

You can also correct errors and make changes in overwrite mode. You toggle 

between insert mode and overwrite mode using the INSERT key. 


10-18 A5E00706944-01


10.5 Editing LAD Elements in the Code Section 

10.5.1 Settings for Ladder Logic Programming 

Setting the Ladder Logic Layout 

You can set the layout for creating programs in the Ladder Logic representation 

type. The format you select (A4 portrait/landscape/maximum size) affects the 

number of Ladder elements that can be displayed in one rung. 

1. Select the menu command Options > Customize. 

2. Select the "LAD/FBD" tab in the following dialog box. 

3. Select the required format from the "Layout" list box. Enter the required format 

size. 

Settings for Printing 

If you want to print out the Ladder code section, you should set the appropriate 

page format before you start to program the code section. 

Settings in the "LAD/FBD" Tab 

In the "LAD/FBD" tab which is accessed using the menu command Options > 

Customize you can make basic settings, e.g. concerning layout and address field 

width. 

10.5.2 Rules for Entering Ladder Logic Elements 

You will find a description of the Ladder Logic programming language 

representation in the "Ladder Logic for S7-300/400 - Programming Blocks" manual 

or in the Ladder Logic online help. 

A Ladder network can consist of a number of elements in several branches. All 

elements and branches must be connected; the left power rail does not count as a 

connection (IEC 1131-3). 

When programming in Ladder you must observe a number of guidelines. Error 

messages will inform you of any errors you make. 

Closing a Ladder Network 

Every Ladder network must be closed using a coil or a box. The following Ladder 

elements must not be used to close a network: 

• Comparator boxes 

• Coils for midline outputs _/(#)_/ 

• Coils for positive _/(P)_/ or negative _/(N)_/ edge evaluation 


A5E00706944-01 10-19


Positioning Boxes 

The starting point of the branch for a box connection must always be the left power 

rail. Logic operations or other boxes can be present in the branch before the box. 

Positioning Coils 

Coils are positioned automatically at the right edge of the network where they form 

the end of a branch. 

Exceptions: Coils for midline outputs _/(#)_/ and positive _/(P)_/ or negative _/(N)_/ 

edge evaluation cannot be placed either to the extreme left or the extreme right in a 

branch. Neither are they permitted in parallel branches. 

Some coils require a Boolean logic operation and some coils must not have a 

Boolean logic operation. 

• Coils which require Boolean logic: 

- Output _/( ), set output _/(S), reset output _/(R) 

- Midline output _/(#)_/, positive edge _/(P)_/, negative edge _/(N)_/ 

- All counter and timer coils 

- Jump if Not _/(JMPN) 

- Master Control Relay On _/(MCR) 

All other coils can either have Boolean logic operations or not. 

The following coils must not be used as parallel outputs: 

• Jump if Not _/(JMPN) 

• Jump _/(JMP) 

• Call from Coil _/(CALL) 

• Return _/(RET) 

Enable Input/Enable Output 

The enable input "EN" and enable output "ENO" of boxes can be connected but 

this is not obligatory. 


10-20 A5E00706944-01


Removing and Overwriting 

If a branch consists of only one element, the whole branch is removed when the 

element is deleted. 

When a box is deleted, all branches which are connected to the Boolean inputs of 

the box are also removed with the exception of the main branch. 

The overwrite mode can be used to simply overwrite elements of the same type. 

Parallel Branches 

• Draw OR branches from left to right. 

• Parallel branches are opened downwards and closed upwards. 

• A parallel branch is always opened after the selected Ladder element. 

• A parallel branch is always closed after the selected Ladder element. 

• To delete a parallel branch, delete all the elements in the branch. When the last 

element in the branch is deleted, the branch is removed automatically. 

Constants 

Binary links cannot be assigned constants (i.e. TRUE or FALSE). Instead, use 

addresses of the data type BOOL. 


A5E00706944-01 10-21


10.5.3 Illegal Logic Operations in Ladder 

Power Flow from Right to Left 

No branches may be created which may cause power to flow in the reverse 

direction. The following figure shows an example: With signal state "0" at I 1.4 a 

power flow from right to left would result at I 6.8. This is not permitted. 

 

( ) 

 

 

 

 

Short Circuit 

No branches may be created which cause a short circuit. The following figure 

shows an example: 

 

( ) 

 


10-22 A5E00706944-01


10.6 Editing FBD Elements in the Code Section 

10.6.1 Settings for Function Block Diagram Programming 

Setting the Function Block Diagram Layout 

You can set the layout for creating programs in the Function Block Diagram 

representation type. The format you select (A4 portrait/landscape/maximum size) 

affects the number of FBD elements that can be displayed in one rung. 


2. Select the "LAD/FBD" tab in the following dialog box. 

3. Select the required format from the "Layout" list box. Enter the required format 

size. 

Settings for Printing 

If you want to print out the FBD code section, you should set the appropriate page 

format before you start to program the code section. 

Settings in the "LAD/FBD" Tab 

In the "LAD/FBD" tab which is accessed using the menu command Options > 

Customize you can make basic settings, e.g. concerning layout and address field 

width. 


A5E00706944-01 10-23


10.6.2 Rules for Entering FBD Elements 

You will find a description of the programming language "FBD" in the "Function 

Block Diagram for S7-300/400 - Programming Blocks" manual or in the FBD online 

help. 

An FBD network can consist of a number of elements. All elements must be 

interconnected (IEC 1131-3). 

When programming in FBD, you must observe a number of rules. Error messages 

will inform you of any errors you make. 

Entering and Editing Addresses and Parameters 

When an FBD element is inserted, the characters ??? and ... are used as token 

characters for addresses and parameters. 

• The red characters ??? stand for addresses and parameters which must be 

connected. 

• The black characters ... stand for addresses and parameters which can be 

connected. 

If you position the mouse pointer on the token characters, the expected data type is 

displayed. 

Positioning Boxes 

You can add standard boxes (flip flops, counters, timers, math operations, etc.) to 

boxes with binary logic operations (&, >=1, XOR). The exceptions to this rule are 

comparison boxes. 

No separate logic operations with separate outputs can be programmed in a 

network. You can, however, assign a number of assignments to a string of logic 

operations with the help of a branch. The following figure shows a network with two 

assignments. 

 

 

 

 

 

 

 

 

 

 

 

 

 


10-24 A5E00706944-01


The following boxes can only be placed at the right edge of the logic string where 

they close the string: 

• Set counter value 

• Assign parameters and count up, assign parameters and count down 

• Assign pulse timer parameters and start, assign extended pulse timer 

parameters and start 

• Assign on-delay/off-delay timer parameters and start 

Some boxes require a Boolean logic operation and some boxes must not have a 

Boolean logic operation. 

Boxes which require Boolean logic: 

• Output, set output, reset output _/[R] 

• Midline output _/[#]_/, positive edge _/[P]_/, negative edge _/[N]_/ 

• All counter and timer boxes 

• Jump if Not _/[JMPN] 

• Master Control Relay On _/[MCR] 

All other boxes can either have Boolean logic operations or not. 

Enable Input/Enable Output 

The enable input "EN" and enable output "ENO" of boxes can be connected but 

this is not obligatory. 

Removing and Overwriting 

When a box is deleted, all branches which are connected to the Boolean inputs of 

the box are also removed with the exception of the main branch. 

The overwrite mode can be used to simply overwrite elements of the same type. 

Constants 

Binary links cannot be assigned constants (i.e. TRUE or FALSE). Instead, use 

addresses of the data type BOOL. 


A5E00706944-01 10-25


10.7 Editing STL Statements in the Code Section 

10.7.1 Settings for Statement List Programming 

Setting the Mnemonics 

You can choose between two sets of mnemonics: 

• German 

• English. 

You set the mnemonics in the SIMATIC Manager with the menu command 

Options > Customize in the "Language" tab before opening a block. While editing 

a block you cannot change the mnemonics. 

You edit the block properties in their own dialog box. 

In the editor you can have a number of blocks open and edit them alternately as 

required. 

10.7.2 Rules for Entering STL Statements 

You will find a description of the Statement List programming language 

representation in the "Statement List for S7-300/400 - Programming Blocks" 

manual or in the STL online help (Language Descriptions). 

When you enter statements in STL in incremental input mode, you must observe 

the following basic guidelines: 

• The order in which you program your blocks is important. Called blocks must be 

programmed before calling blocks. 

• A statement is made up of a label (optional), instruction, address, and comment 

(optional). 

Example: M001: A I 1.0 //Comment 

• Every statement has its own line. 

• You can enter up to 999 networks in a block. 

• Each network can have up to approximately 2000 lines. If you zoom in or out, 

you can enter more or fewer lines accordingly. 

• When entering instructions or absolute addresses, there is no distinction made 

between lower and upper case. 


10-26 A5E00706944-01


10.8 Updating Block Calls 

You can use the menu command Edit > Block Call > Update in "LAD/STL/FBD - 

Programming S7 Blocks" to automatically update block calls which have become 

invalid. After you have carried out the following interface changes, you must 

perform an update: 

• Inserted new formal parameters 

• Deleted formal parameters 

• Changed the name of formal parameters 

• Changed the type of formal parameters 

• Changed the order of formal parameters. 

When assigning formal and actual parameters, you must follow the following rules 

in the order specified: 

1. Same parameter names: 

The actual parameters are assigned automatically, if the name of the formal 

parameter has remained the same. 

Special case: In Ladder Logic and Function Block Diagram, the preceding link 

for binary input parameters can only be assigned automatically if the data type 

(BOOL) is the same. If the data type has been changed, the preceding link is 

retained as an open branch. 

2. Same parameter data types: 

After the parameters with the same name have been assigned, as yet 

unassigned actual parameters are assigned to formal parameters with the 

same data type as the "old" formal parameter. 

3. Same parameter position: 

After you have carried out rules 1 and 2, any actual parameters which have still 

not been assigned are now assigned to the formal parameters according to 

their parameter position in the "old" interface. 

4. If actual parameters cannot be assigned using the three rules described above, 

they are deleted or, in the case of binary preceding links in Ladder Logic or 

Function Block Diagram, they are retained as open branches. 

After carrying out this function, check the changes you have made in the variable 

declaration table and in the code section of the program. 


A5E00706944-01 10-27


10.8.1 Changing Interfaces 

You can also use the incremental Editor to modify the interfaces of offline blocks 

that have been edited with STEP 7, version 5: 

1. Make sure that all the blocks have been compiled with STEP 7, version 5. To 

do this, generate a source file for all the blocks and compile it. 

2. Modify the interface of the relevant block. 

3. Now open all the calling blocks one after another - the corresponding calls are 

displayed in red. 

4. Select the menu command Edit > Block Call > Update. 

5. Generate the relevant instance data blocks again. 

Note 

• Interface changes to a block opened online may cause the CPU to go into 

STOP mode. 

• Rewiring block calls 

First modify the numbers of the called blocks and then execute the Rewire 

function to match up the calls. 


10-28 A5E00706944-01


10.9 Saving Logic Blocks 

To enter newly created blocks or changes in the code section of logic blocks or in 

declaration tables in the programming device database, you must save the 

respective block. The data are then written to the hard disk of the programming 

device. 

To save blocks on the hard disk of the programming device: 

1. Activate the working window of the block you want to save. 

2. Select one of the following menu commands: 

- File > Save saves the block under the same name. 

- File > Save As saves the block under a different S7 user program or under 

a different name. Enter the new path or new block name in the dialog box 

which then appears. 

In both cases the block is saved only if its syntax contains no errors. Syntax errors 

are identified immediately when the block is created and are then displayed in red. 

These errors must be corrected before the block can be saved. 

Note 

• You can also save blocks or source files beneath other projects or libraries in 

the SIMATIC Manager (by dragging & dropping, for example). 

• You can only save blocks or complete user programs to a memory card in the 


• If problems occur when saving or compiling large blocks, you should 

reorganize the project. Use the menu command File > Reorganize in the 

SIMATIC Manager to do this. Then try to save or compile again. 


A5E00706944-01 10-29



10-30 A5E00706944-01

11 Creating Data Blocks 

11.1 Basic Information on Creating Data Blocks 

The data block (DB) is a block in which you can, for example, store values for your 

machine or plant to access. In contrast to a logic block that is programmed with 

one of the programming languages Ladder Logic, Statement List, or Function Block 

Diagram, a data block contains only the variable declaration section. This means 

the code section is irrelevant here and so is programming networks. 

When you open a data block, you can either view the block in the declaration view 

or in the data view. You can toggle between the two views with the menu 

commands View > Declaration View and View > Data View. 

Declaration View 

You use the declaration view if you want to: 

• View or determine the data structure of shared data blocks, 

• View the data structure of data blocks with an associated user-defined data type 

(UDT), or 

• View the data structure of data blocks with an associated function block (FB). 

The structure of data blocks that are associated with a function block or userdefined 

data type cannot be modified. To modify them you must first modify the 

associated FB or UDT and then create a new data block. 

Data View 

You use the data view if you want to modify data. You can only display, enter, or 

change the actual value of each element in the data view. In the data view of data 

blocks, the elements of variables with complex data types are listed individually 

with their full names. 

Differences between Instance Data Blocks and Shared Data Blocks 

A shared data block is not assigned to a logic block. It contains values required by 

the plant or machine and can be called directly at any point in the program. 

An instance data block is a block that is assigned directly to a logic block, such as 

a function block. The instance data block contains the data that were stored in a 

function block in the variable declaration table. 


A5E00706944-01 11-1

Creating Data Blocks 

11.2 Declaration View of Data Blocks 

With data blocks which are not globally shared, the declaration view cannot be 

changed. 

Column 

Address 

Declaration 

Name 

Type 

Initial Value 

Comment 

Explanation 

Displays the address which STEP 7 automatically assigns for the variable when you 

finish entering a declaration. 

This column is only displayed for instance data blocks. It shows you how the variables in 

the variable declaration of the function block are declared: 

• Input parameter (IN) 

• Output parameter (OUT) 

• In/out parameter (IN_OUT) 

• Static data (STAT) 

Enter the symbolic name you have to assign to each variable here. 

Enter the data type you want to assign to the variable (BOOL, INT, WORD, ARRAY, 

etc.). The variables can have elementary data types, complex data types, or userdefined 

data types. 

Here you can enter the initial value if you do not want the software to use the default 

value for the data type entered. All values must be compatible with the data type. 

When you save a block for the first time, the initial value is used as the current value if 

you have not explicitly defined actual values for the variables. 

Please note: Initial values cannot be downloaded to the CPU. 

Enter a comment in this field helps to document the variables. The comment can have 

up to 79 characters. 


11-2 A5E00706944-01


11.3 Data View of Data Blocks 

The data view shows you the current values of all variables in the data block. You 

can only change these values in the data view. The table representation in this 

view is the same for all shared data blocks. For instance data blocks an additional 

"Declaration" column is displayed. 

For variables with complex data types or user-defined data types, all elements are 

displayed in their own row with their full symbolic name in the data view. If the 

elements are in the IN_OUT area of an instance data block, the pointer points to 

the complex or user-defined data type in the "Actual Value" column. 

The data view displays the following columns: 

Column 

Address 

Declaration 

Name 

Type 

Initial Value 

Actual Value 

Comment 

Explanation 

Displays the address which STEP 7 automatically assigns for the variable. 

This column is only displayed for instance data blocks. It shows you how the variables 

in the variable declaration of the function block are declared: 





The symbolic name assigned in the variable declaration for the variable. You cannot 

edit this field in the data view. 

Displays the data type defined for the variable. 

For shared data blocks, only the elementary data types are listed here because the 

elements are listed individually in the data view for variables with complex or userdefined 

data types. 

For instance data blocks the parameter types are also displayed, for in/out parameters 

(IN_OUT) with complex or user-defined data types, a pointer points to the data type in 

the "Actual Value" column. 

The initial value that you entered for the variable if you do not want the software to use 

the default value for the specified data type. 

When you save a data block for the first time, the initial value is used as the current 

value if you have not explicitly defined actual values for the variables. 

Please note: Unlike with actual values, initial values cannot be downloaded to the 

CPU. 

Offline: The value that the variable had when the data block was opened or to which 

you last changed it and saved it (even if you opened the data block online, this display 

is not updated). 

Online: The current value on opening the data block is displayed but not updated 

automatically. To update the view, press F5. 

You can edit this field if it does not belong to an in/out parameter (IN_OUT) with a 

complex or user-defined data type. All values must be compatible with the data type. 

Please note. Only current values can be downloaded to the CPU/ 

The comment entered to document the variable. You cannot edit this field in the data 

view. 


A5E00706944-01 11-3


11.4 Editing and Saving Data Blocks 

11.4.1 Entering the Data Structure of Shared Data Blocks 

If you open a data block which is not assigned to a user-defined data type or 

function block, you can define its structure in the declaration view of the data block. 

With data blocks which are not shared, the declaration view cannot be changed. 

1. Open a shared data block, meaning a block which is not associated with a 

UDT or FB. 

2. Display the declaration view of the data block if this view is not set already. 

3. Define the structure by filling out the table displayed in accordance with the 

information below. 

With data blocks which are not shared, the declaration view cannot be modified. 

Column 

Address 

Name 

Type 

Initial Value 

Comment 

Explanation 

Displays the address which STEP 7 automatically assigns for the variable when you finish 

entering a declaration. 


Enter the data type you want to assign to the variable (BOOL, INT, WORD, ARRAY, etc.). 

The variables can have elementary data types, complex data types, or user-defined data 

types. 



When you save a block for the first time, the initial value is used as the actual value if you 

have not explicitly defined actual values for the variables. 

Entering an optional comment in this field helps to document the variable. The comment 

can have up to 80 characters. 


11-4 A5E00706944-01


11.4.2 Entering and Displaying the Data Structure of Data Blocks 

Referencing an FB (Instance DBs) 

Input 

When you associate a data block with a function block (instance DB), the variable 

declaration of the function block defines the structure of the data block. Any 

changes can only be made in the associated function block. 

1. Open the associated function block (FB). 

2. Edit the variable declaration of the function block. 

3. Create the instance data block again. 

Display 

In the declaration view of the instance data block you can display how the variables 

in the function block were declared. 

1. Open the data block. 


3. See below for more information on the table displayed. 

With data blocks which are not shared, the declaration view cannot be changed. 

Column Explanation 

Address Displays the address which STEP 7 automatically assigns for the variable. 

Declaration This column shows you how the variables in the variable declaration of the function block 

are declared: 





The declared temporary local data of the function block are not in the instance data block. 

Name The symbolic name assigned in the variable declaration of the function block. 

Type Displays the data type assigned in the variable declaration of the function block. The 

variables can have elementary data types, complex data types, or user-defined data types. 

If additional function blocks are called within the function block for whose call static 

variables have been declared, a function block or a system function block (SFB) can also 

be specified here as the data type. 

Initial Value The initial value that you entered for the variable in the variable declaration of the function 

block if you do not want the software to use the default value. 

When you save a data block for the first time, the initial value is used as the actual value if 

you have not explicitly defined actual values for the variables. 

Comment The comment entered in the variable declaration for the function block to document the 

data element. You cannot edit this field. 


A5E00706944-01 11-5


Note 

For data blocks that are assigned to a function block, you can only edit the actual 

values for the variables. To enter actual values for the variables, you must be in 

the data view of data blocks. 


11-6 A5E00706944-01


11.4.3 Entering the Data Structure of User-Defined Data Types (UDT) 

1. Open the user-defined data type (UDT). 

2. Display the declaration view if this view is not set already. 

3. Define the structure of the UDT by determining the sequence of variables, their 

data type, and an initial value if required using the information in the table 

below. 

4. You complete the entry of a variable by exiting the row with the TAB key or 

RETURN. 

Column 

Address 

Name 

Type 

Initial Value 

Comment 

Explanation 

Displays the address which STEP 7 automatically assigns for the variable when you 

finish entering a declaration. 


Enter the data type you want to assign to the variable (BOOL, INT, WORD, ARRAY, 

etc.). The variables can have elementary data types, complex data types, or their own 

user-defined data types. 



When you save an instance of the user-defined data type (or a variable, or a data block) 

for the first time, the initial value is used as the actual value if you have not explicitly 

defined actual values for the variables. 

Entering a comment in this field helps to document the variables. The comment can 

have up to 80 characters. 


A5E00706944-01 11-7


11.4.4 Entering and Displaying the Structure of Data Blocks 

Referencing a UDT 

Input 

When you assign a data block to a user-defined data type, the data structure of the 

user-defined data type defines the structure of the data block. Any changes can 

only be made in the associated user-defined data type. 

1. Open the user-defined data type (UDT). 

2. Edit the structure of the user-defined data type. 

3. Create the data block again. 

Display 

You can only display how the variables were declared in the user-defined data type 

in the declaration view of the data block. 

1. Open the data block. 


3. See below for more information on the table displayed. 

The declaration view cannot be modified. Any changes can only be made in the 

associated user-defined data type. 

Column 

Address 

Name 

Type 

Initial Value 

Comment 

Explanation 

Displays the address which STEP 7 automatically assigns for the variable. 

The symbolic name assigned in the variable declaration of the user data type. 

Displays the data types assigned in the variable declaration of the user-defined data 

type. The variables can have elementary data types, complex data types, or userdefined 

data types. 

The initial value that you entered for the variable in the user-defined data type if you do 

not want the software to use the default value. 

When you save a data block for the first time, the initial value is used as the actual 

value if you have not explicitly defined actual values for the variables. 

The comment entered in the variable declaration for the user-defined data type to 

document the data element. 

Note 

For data blocks that are assigned to a user-defined data type, you can only edit the 

actual values for the variables. To enter actual values for the variables, you must 

be in the data view of data blocks. 


11-8 A5E00706944-01


11.4.5 Editing Data Values in the Data View 

Editing actual values is only possible in the data view of data blocks. 

1. If necessary, toggle to the table display in the data view using the menu 

command View > Data View. 

2. Enter the required actual values for the data elements in the fields of the 

column "Actual Value." The actual values must be compatible with the data 

type of the data elements. 

Any incorrect entries (for example, if an actual value entered is not compatible with 

the data type) made during editing are recognized immediately and shown in red. 

These errors must be corrected before saving the data block. 

Note 

Any changes to the data values are only retained once the data block has been 

saved. 

11.4.6 Resetting Data Values to their Initial Values 

Resetting data values is only possible in the data view of data blocks. 

1. If necessary, toggle to the table display in the data view using the menu 

command View > Data View. 

2. Select the menu command Edit > Initialize Data Block to do this. 

All variables are assigned their intended initial value again, meaning the actual 

values of all variables are overwritten by their respective initial value. 

Note 

Any changes to the data values are only retained once the data block has been 

saved. 


A5E00706944-01 11-9


11.4.7 Saving Data Blocks 

To enter newly created blocks or changed data values in data blocks in the 

programming device database, you must save the respective block. The data are 

then written to the hard disk of the programming device. 

To save blocks on the hard disk of the programming device: 

1. Activate the working window of the block you want to save. 

2. Select one of the following menu commands: 

- File > Save saves the block under the same name. 

- File > Save As saves the block under a different S7 user program or under 

a different name. Enter the new path or new block name in the dialog box 

which then appears. With data blocks, you may not use the name DB0 

because this number is reserved for the system. 

In both cases the block is saved only if its syntax contains no errors. Syntax errors 

are identified immediately when the block is created and are then displayed in red. 

These errors must be corrected before the block can be saved. 

Note 

• You can also save blocks or source files beneath other projects or libraries in 

the SIMATIC Manager (by dragging & dropping, for example). 

• You can only save blocks or complete user programs to a memory card in the 


• If problems occur when saving or compiling large blocks, you should 

reorganize the project. Use the menu command File > Reorganize in the 

SIMATIC Manager to do this. Then try to save or compile again. 


11-10 A5E00706944-01

12 Parameter Assignment for Data Blocks 

The function "Parameter Assignment for Data Blocks" allows you to do the 

following outside the LAD/STL/FBD program editor: 

• Edit and download the actual values of instance data blocks to the PLC, without 

having to load the entire data block. 

• Monitor instance data blocks online. 

• Use the "S7_techparam" system attribute (Technological Functions) to easily 

assign parameters to instance data blocks and multiple instances and monitor 

them online. 

Procedure: 

1. In the SIMATIC Manager, double-click the instance data block to open it. 

2. Answer the prompt asking if you want to open the function "Parameter 

Assignment for Data Blocks" with "Yes". Result: the instance DB is opened in 

the "Parameter Assignment for Data Blocks" application. 

3. Choose the view in which the data block should be displayed by selecting the 

menu command View > Data View or View > Declaration View.In the case of 

instance data blocks or multiple instances with the "S7_techparam" system 

attribute, the "technological parameters" view is automatically opened. 

4. Edit the instance date block as needed. Any pertinent information, warnings or 

errors will be displayed in the message window. To go to the location of a 

warning or error, double-click on the corresponding warning or error. 

5. Download the changed actual value from the programming device (PG) to the 

CPU that you have assigned to the current S7 program (menu command 

PLC > Download Parameter Setting Data). 

6. Select the menu command Debug > Monitor to display the program status for 

the opened blocks and then monitor the editing of the loaded actual values 

online. 

Note 

You can recognize data blocks that have the "S7_techparam" system. To 

determine whether a block has this system attribute, go to the SIMATIC Manager 

and select the block. Then select the menu command Edit > Object Properties 

and open the "Attributes" tab. 


A5E00706944-01 12-1

Parameter Assignment for Data Blocks 

12.1 Assigning Parameters to Technological Functions 

With the function "Parameter Assignment for Data Blocks" you can easily assign 

parameters to the temperature controller blocks FB 58 "TCONT_CP" and FB 59 

"TCONT_S" that are supplied in the standard library and monitor them online. 

To do so, proceed as follows: 

1. In the SIMATIC Manager, open the STEP 7 standard library by selecting the 

menu command File > Open > Libraries. 

2. Select "PID Control Blocks" and then click on "Blocks". Here you will find the 

following function blocks with the attribute "S7_techparam": 

- FB 58 "TCONT_CP": Temperature controller for actuators with continuous 

or pulsing input signals 

- FB 59 "TCONT_S": Temperature controller for integral-type actuators 

3. Copy the appropriate function block (FB 58 or FB 59) from the standard library 

into your project. 

4. Select the menu command Insert > S7 Block > Data Block to create an 

instance DB for the FB that you selected. 

5. In the SIMATIC Manager, double-click the instance DB to open it and start the 

function "Parameter Assignment for Data Blocks". 

Result: The instance DB is opened in the technological view. You can now 

easily assign parameters to the instance DB and monitor it online. 

6. Enter suitable controller values in the technological view. Any pertinent 

information, warnings or errors will be displayed in the message window. To go 

to the location of a warning or error, double-click on the corresponding warning 

or error. 

Note 

You can determine if blocks that have the system attribute "S7_techparam" by 

selecting a block in the SIMATIC Manager, selecting the menu command Edit > 

Object Properties and then opening the "Attributes" tab. 


12-2 A5E00706944-01

13 Creating STL Source Files 

13.1 Basic Information on Programming in STL Source Files 

You can enter your program or parts of it as an STL source file and then compile it 

into blocks in one step. The source file can contain the code for a number of 

blocks, which are then compiled as blocks in one compilation run. 

Creating programs using a source file has the following advantages: 

• You can create and edit the source file with any ASCII editor, then import it and 

compile it into blocks using this application. The compilation process creates the 

individual blocks and stores them in the S7 user program. 

• You can program a number of blocks in one source file. 

• You can save a source file even if it contains syntax errors. This is not possible 

if you create logic blocks using an incremental syntax check. However, the 

syntax errors are only reported once you compile the source file. 

The source file is created in the syntax of the programming language 

representation Statement List (STL). The source file is given its structure of blocks, 

variable declaration, and networks using keywords. 

When you create blocks in STL source files you should note the following: 

• Guidelines for Programming STL Source Files 

• Syntax and Formats for Blocks in STL Source Files 

• Structure of Blocks in STL Source Files 


A5E00706944-01 13-1

Creating STL Source Files 

13.2 Rules for Programming in STL Source Files 

13.2.1 Rules for Entering Statements in STL Source Files 

An STL source file consists mainly of continuous text. To enable the file to be 

compiled into blocks, you must observe certain structures and syntax rules. 

The following general guidelines apply to creating user programs as STL source 

files: 

Topic 

Syntax 

CALL 

Rule 

The syntax of the STL statements is the same as in the incremental Statement 

List editor. One exception to this is the CALL instruction. 

In a source file, you enter parameters in brackets. The individual parameters are 

separated by a comma. 

Example: FC call (one line) 

CALL FC10 (param1 :=I0.0,param2 :=I0.1); 

Example: FB call (one line) 

CALL FB10, DB100 (para1 :=I0.0,para2 :=I0.1); 

Example: FB call (more than one line) 

CALL FB10, DB100 ( 

para1 :=I0.0, 

para2 :=I0.1); 

Note: 

When calling a block, transfer the parameters in the defined order in the ASCII 

Editor. Otherwise the comment assignment for these lines may not match in the 

STL and source file views. 

Upper/lower case 

Semicolon 

Double slash (//) 

The editor in this application is not case-sensitive, the exception to this being 

system attributes and jump labels. When entering strings (data type STRING) you 

must also observe upper and lower case. 

Keywords are shown in upper case. When compiled, upper and lower case are 

not observed; therefore you can enter keywords in upper or lower case or a 

mixture of the two. 

Designate the end of every STL statement and every variable declaration with a 

semicolon (;). You can enter more than one statement per line. 

Begin every comment with a double slash (//) and end the comment with 

RETURN (or line feed). 


13-2 A5E00706944-01


13.2.2 Rules for Declaring Variables in STL Source Files 

For every block in the source file you must declare the required variables. 

The variable declaration section comes before the code section of the block. 

The variables must - if they are being used - be declared in the correct sequence 

for declaration types. This means all variables of one declaration type are together. 

For Ladder, Function Block Diagram, and Statement List you fill out a variable 

declaration table, but here you have to work with the relevant keywords. 

Keywords for Variable Declaration 

Declaration Type Keywords Valid for... 

Input parameters 

"VAR_INPUT" 

FBs, FCs 

Declaration list 

"END_VAR" 

Output parameters 

"VAR_OUTPUT" 

FBs, FCs 


"END_VAR" 

In/out parameters 

"VAR_IN_OUT" 

FBs, FCs 


"END_VAR" 

Static variables 

"VAR" 

FBs 


"END_VAR" 

Temporary variables 

"VAR_TEMP" 


END_VAR 

OBs, FBs, FCs 

The keyword END_VAR denotes the end of a declaration list. 

The declaration list is a list of the variables of a declaration type in which default 

values can be assigned to the variables (exception: VAR_TEMP). The following 

example shows the structure of an entry in the declaration list: 

Duration_Motor1 : S5TIME := S5T#1H_30M ; 

Variable Data type Default value 

Note 

• The variable symbol must start with a letter. You may not assign a symbolic 

name for a variable that is the same as one of the reserved keywords. 

• If variable symbols are identical in the local declarations and in the symbol 

table, you can code local variables by placing # in front of the name and 

putting variables in the symbol table in quotation marks. Otherwise, the block 

interprets the variable as a local variable. 


A5E00706944-01 13-3


13.2.3 Rules for Block Order in STL Source Files 

Called blocks precede the calling blocks. This means: 

• The OB1 used in most cases, which calls other blocks, comes last. Blocks that 

are called from OB1 must precede it. 

• User-defined data types (UDT) precede the blocks in which they are used. 

• Data blocks with an associated user-defined data type (UDT) follow the userdefined 

data type. 

• Shared data blocks precede all blocks from which they are called. 

• Instance data blocks follow the associated function block. 

• DB0 is reserved. You cannot create a data block with this name. 

13.2.4 Rules for Setting System Attributes in STL Source Files 

System attributes can be assigned to blocks and parameters. They control the 

message configuration and connection configuration, operator interface functions, 

and process control configuration. 

The following applies when entering system attributes in source files: 

• The keywords for system attributes always start with S7_. 

• The system attributes are placed in braces (curly brackets). 

• Syntax: {S7_identifier := 'string'} 

a number of identifiers are separated by ";". 

• System attributes for blocks come before the block properties and after the 

keywords ORGANIZATION_ and TITLE. 

• System attributes for parameters are included with the parameter declaration, 

meaning before the colon for the data declaration. 

• A distinction is made between upper and lower case characters. This means 

that the correct use of upper and lower case characters is important when 

entering system attributes. 

The system attributes for blocks can be checked or changed in incremental input 

mode using the menu command File > Properties under the "Attributes" tab. 

The system attributes for parameters can be checked or changed in incremental 

input mode using the menu command Edit > Object Properties. The cursor must 

be positioned in the name field of the parameter declaration. 


13-4 A5E00706944-01


13.2.5 Rules for Setting Block Properties in STL Source Files 

You can more easily identify the blocks you created if you use block properties and 

you can also protect these blocks from unauthorized changes. 

The block properties can be checked or changed in incremental input mode using 

the menu command File > Properties under the "General - Part 1" and "General - 

Part 2" tabs. 

The other block properties can only be entered in the source file. 

The following applies in source files: 

• Block properties precede the variable declaration section. 

• Each block property has a line of its own. 

• The line ends with a semicolon. 

• The block properties are specified using keywords. 

• If you enter block properties, they must appear in the sequence shown in the 

Table of Block Properties. 

• The block properties valid for each block type are listed in the Assignment: 

Block Property to Block Type. 

Note 

The block properties are also displayed in the SIMATIC Manager in the object 

properties for a block. The properties AUTHOR, FAMILY, NAME, and VERSION 

can also be edited there. 


A5E00706944-01 13-5


Block Properties and Block Order 

When entering block properties, you should observe the input sequence shown in 

the following table: 

Order Keyword / Property Meaning Example 

1. [KNOW_HOW_PROTECT] Block protection; a block compiled 

with this option does not allow its 

code section to be viewed. The 

interface for the block can be 

viewed, but it cannot be changed. 

KNOW_HOW_PROTECT 

2. [AUTHOR:] Name of author: company name, 

department name, or other name 


3. [FAMILY:] Name of block family: for 

example, controllers 


AUTHOR : Siemens, but 

no keyword 

FAMILY : controllers, but 

no keyword 

4. [NAME:] Block name (max. 8 characters) NAME : PID, but no 

keyword 

5. [VERSION: int1 . int2] Version number of block 

VERSION : 3.10 

(both numbers between 0 and 15, 

meaning 0.0 to 15.15) 

6. [CODE_VERSION1] ID whether a function block can CODE_VERSION1 

have multiple instances declared 

or not. If you want to declare 

multiple instances, the function 

block should not have this 

property 

7. [UNLINKED] for DBs only Data blocks with the UNLINKED 

property are only stored in the 

load memory. They take up no 

space in the working memory and 

are not linked to the program. 

They cannot be accessed with 

MC7 commands. The contents of 

such a DB can be transferred to 

the working memory only with 

SFC 20 BLKMOV (S7-300. S7- 

400) or SFC 83 READ_DBL (S7- 

300C). 

8. [READ_ONLY] for DBs only Write protection for data blocks; FAMILY= Examples 

its data can only be read and VERSION= 3.10 

cannot be changed 

READ_ONLY 


13-6 A5E00706944-01


13.2.6 Permitted Block Properties for Each Block Type 

The following table shows which block properties can be declared for which block 

types: 

Property OB FB FC DB UDT 

KNOW_HOW_PROTECT • • • • − 

AUTHOR • • • • − 

FAMILY • • • • − 

NAME • • • • − 

VERSION • • • • − 

UNLINKED − − − • − 

READ_ONLY − − − • − 

Setting Block Protection with KNOW_HOW_PROTECT 

You can protect your blocks from unauthorized users by setting block protection 

using the keyword KNOW_HOW_PROTECT when you program the block in the 

STL source file. 

This block protection has the following consequences: 

• If you want to view a compiled block at a later stage in the incremental STL, 

FBD, or Ladder editors, the code section of the block cannot be displayed. 

• The variable declaration list for the block displays only the variables of the 

declaration types var_in, var_out, and var_in_out. The variables of the 

declaration types var_stat and var_temp remain hidden. 

• The keyword KNOW_HOW_PROTECT is entered before any other block 

properties. 

Setting Write Protection for Data Blocks with READ_ONLY 

For data blocks, you can set up write protection so that the block is not overwritten 

during program processing. The data block must exist in the form of an STL source 

file to do this. 

Use the keyword READ_ONLY in the source file to set write protection. This 

keyword must appear immediately before the variable declarations in a line on its 

own. 

13.3 Structure of Blocks in STL Source Files 

The blocks in STL source files are structured using keywords. Depending on the 

type of block, there are differences in the structure of: 

• Logic blocks 


A5E00706944-01 13-7


• Data blocks 

• User-defined data types (UDT) 

13.3.1 Structure of Logic Blocks in STL Source Files 

A logic block is made up of the following sections, each of which is identified by the 

corresponding keyword: 

• Block start, 

• identified by keyword and block number or block name, for example 

- "ORGANIZATION_BLOCK OB1" for an organization block, 

- "FUNCTION_BLOCK FB6" for a function block, or 

- "FUNCTION FC1 : INT" for a function. With functions the function type is 

also specified. This can be an elementary or complex data type (with the 

exception of ARRAY and STRUCT) and defines the data type of the return 

value (RET_VAL). If no value is to be returned, the keyword VOID is given. 

• Optional block title introduced by the keyword "TITLE" (max. length of title: 64 

characters) 

• Additional comments, beginning with a double slash // at the start of the line 

• Block properties (optional) 

• Variable declaration section 

• Code section, beginning with "BEGIN." The code section consists of one or 

more networks that are identified by "NETWORK." You cannot enter a network 

number. 

• Optional network for each network used, introduced by the keyword "TITLE =" 

(max. length of title: 64 characters) 

• Additional comments for each network, beginning with a double slash // at the 

start of the line 

• Block end, identified by END_ORGANIZATION_BLOCK, 

END_FUNCTION_BLOCK, or END_FUNCTION 

• A blank must be placed between the block type and the block number. The 

symbolic block name can be identified by quotation marks to ensure that the 

symbolic names of local variables and names in the symbol table remain 

unique. 


13-8 A5E00706944-01


13.3.2 Structure of Data Blocks in STL Source Files 

A data block consists of the following areas that are introduced by their respective 

keywords: 

• Block start, identified by keyword and block number or block name, for example, 

DATA_BLOCK DB26 

• Reference to an associated UDT or function block (optional) 

• Optional block title introduced by the keyword TITLE = (entries longer than 64 

characters are cut off) 

• Optional block comment, beginning with a double slash // 

• Block properties (optional) 

• Variable declaration section (optional) 

• Assignment section with default values, beginning with BEGIN (optional) 

• Block end, identified by END_DATA_BLOCK 

There are three types of data block: 

• Data blocks, user-defined 

• Data blocks with an associated user-defined data type (UDT) 

• Data blocks with an associated function block (known as "instance" data blocks) 

13.3.3 Structure of User-Defined Data Types in STL Source Files 

A user-defined data type consists of the following areas that are introduced by their 

respective keywords: 

• Block start, identified by keyword TYPE and number or name, for example, 

TYPE UDT20 

• Structured data type 

• Block end, identified by END_TYPE 

When you enter a user-defined data type, you must ensure that user-defined data 

types precede the blocks in which they are used. 


A5E00706944-01 13-9


13.4 Syntax and Formats for Blocks in STL Source Files 

The format tables show the syntax and formats that you should observe when 

programming STL source files. The syntax is represented as follows: 

• Each element is described in the right column. 

• Any elements that must be entered are shown in quotation marks. 

• The square brackets [...] mean that the contents of these brackets are optional. 

• Keywords are given in upper case letters. 

13.4.1 Format Table of Organization Blocks 

The following table shows a brief list of the format for organization blocks in an STL 

source file: 

Structure 

Description 

"ORGANIZATION_BLOCK" ob_no 

or ob_name 

ob_no is the block number, for example: OB1; 

ob_name is the symbolic name of the block as 

defined in the symbol table 

[TITLE= ] 

Block title (entries longer than 64 characters are cut 

off) 

[Block comment] Comments can be entered after "//" 

[System attributes for blocks] System attributes for blocks 

[Block properties] 

Block properties 

Variable declaration section Declaration of temporary variables 

"BEGIN" 

Keyword to separate the variable declaration section 

from the list of STL instructions 

NETWORK 

Start of a network 

[TITLE= ] 

Network title (max. 64 characters) 

[Network comment] Comments can be entered after "//" 

List of STL instructions 

Block instructions 

"END_ORGANIZATION_BLOCK" Keyword to end organization block 


13-10 A5E00706944-01


13.4.2 Format Table of Function Blocks 

The following table shows a brief list of the format for function blocks in an STL 

source file: 

Structure 

Description 

"FUNCTION_BLOCK" fb_no or 

fb_name 

fb_no is the block number, for example FB6; 

fb_name is the symbolic name of the block as 


[TITLE= ] 

Block title (entries longer than 64 characters are cut 

off) 





Variable declaration section Declaration of input, output, and in/out parameters, 

and temporary or static variables 

The declaration of the parameters may also contain 

the declarations of the system attributes for 

parameters. 

"BEGIN" 

Keyword to separate the variable declaration section 

from the list of STL instructions 

NETWORK 


[TITLE= ] 





"END_FUNCTION_BLOCK Keyword to end function block 


A5E00706944-01 13-11


13.4.3 Format Table of Functions 

The following table shows a brief list of the format for functions in an STL source 

file: 

Structure 

"FUNCTION" 

fc_no : fc_type or 

fc_name : fc_type 

Description 

fc_no is the block number, for example FC5; 

fc_name is the symbolic name of the block as 

defined in the symbol table; 

fc_type is the data type of the return value 

(RET_VAL) of the function. This can be an 

elementary or complex data type (with the 

exception of ARRAY and STRUCT) or VOID. 

[TITLE= ] 

If you want to use system attributes 

for the return value (RET_VAL), you must enter the 

system attributes for parametersin front of the colon 

for the data declaration. 

Block title (entries longer than 64 characters are 

cut off) 





Variable declaration section 

Declaration of input, output, and in/out parameters, 

and temporary variables 

"BEGIN" 

Keyword to separate the variable declaration 

section from the list of STL instructions 

NETWORK 


[TITLE= ] 





"END_FUNCTION" 

Keyword to end function 


13-12 A5E00706944-01


13.4.4 Format Table of Data Blocks 

The following table shows a brief list of the format for data blocks in an STL source 

file: 

Structure 

Description 

"DATA_BLOCK" db_no or db_name db_no is the block number, for example DB5; 

db_name is the symbolic name of the block as 


[TITLE= ] 

Block title (entries longer than 64 characters are 

cut off) 





Declaration section 

Declaration whether the block is associated with a 

UDT or an FB, given as a block number or 

symbolic name as defined in the symbol table, or 

as a complex data type 

"BEGIN" 

Keyword to separate the declaration section from 

the list of value assignments 

[Assignment of initial values] Variables can have specific initial values assigned. 

Individual variables either have constants assigned 

or a reference is made to other blocks. 

"END_DATA_BLOCK" 

Keyword to end data block 


A5E00706944-01 13-13


13.5 Creating STL Source Files 

13.5.1 Creating STL Source Files 

The source file must be created in the source file folder beneath the S7 program. 

You can create source files in the SIMATIC Manager or the editor window. 

Creating Source Files in the SIMATIC Manager 

1. Open the appropriate "Source Files" folder by double-clicking on it. 

2. To insert an STL source file select the menu command Insert > S7 Software > 

STL Source File. 

Creating Source Files in the Editor Window 

1. Select the menu command File > New. 

2. In the dialog box, select the source file folder of the same S7 program that 

contains the user program with the blocks. 

3. Enter a name for the new source file. 

4. Confirm with "OK". 

The source file is created under the name you entered and is displayed in a 

window for editing. 

13.5.2 Editing S7 Source Files 

The programming language and editor with which a source file is edited can be set 

in the object properties for the source file. This ensures that the correct editor and 

the correct programming language are started when the source file is opened for 

editing. The STEP 7 Standard package supports programming in STL source files. 

Other programming languages are also available as optional packages. You can 

only select the menu command to insert the source file if the corresponding 

software option is loaded on your computer. 

To edit an S7 source file, proceed as follows: 


2. Start the editor required for editing as follows: 

- Double-click the required source file in the right half of the window. 

- Select the required source file in the right half of the window and select the 

menu command Edit > Open Object. 


13-14 A5E00706944-01


13.5.3 Setting The Layout of Source Code Text 

To improve readability of text in source files, select menu command Options > 

Settings and the "Source Code" tab. Specify the font, font style and color for the 

various elements of the source code. 

For example, you can specify to display line numbers and to display keywords in 

upper case letters. 

13.5.4 Inserting Block Templates in STL Source Files 

Block templates for organization blocks (OB), function blocks (FB), functions (FC), 

data blocks (DB), instance data blocks, data blocks with associated user-defined 

data types, and user-defined data types (UDT) are available for programming in 

STL source files. The block templates make it easier to enter blocks in your source 

file and to observe syntax and structure guidelines. 

To insert a block template, proceed as follows: 

1. Activate the window of the source file in which you want to insert a block 

template. 

2. Position the cursor at the point in the file after which you want to insert the 

block template. 

3. Select one of the menu commands Insert > Block Template > 

OB/FB/FC/DB/Instance DB/DB Referencing UDT/UDT. 

The block template is inserted in the file after the cursor position. 

13.5.5 Inserting the Contents of Other STL Source Files 

You can insert the contents of other source files into your STL source file. 


1. Activate the window of the source file in which you want to insert the contents 

of another source file. 

2. Position the cursor at the location in the file after which you want to insert the 

source file. 

3. Select the menu command Insert > Object > File. 

4. Select the required source file in the dialog box which appears. 

The contents of the selected source file are inserted after the cursor position. Line 

feeds (carriage returns) are retained. 


A5E00706944-01 13-15


13.5.6 Inserting Source Code from Existing Blocks in STL Source Files 

You can insert the source code from other blocks into your STL source file which 

were created in Ladder, Function Block Diagram, or Statement List. This is 

possible for organization blocks (OB), function blocks (FB), functions (FC), data 

blocks (DB), and user-defined data types (UDT). 


1. Activate the window of the source file in which you want to insert a block. 

2. Position the cursor at the location in the file after which you want to insert the 

source code from the block. 

3. Select the menu command Insert > Object > Block. 

4. Select the required block in the dialog box which appears. 

An equivalent source file is generated from the block. The contents of the source 

file are inserted after the cursor position. 

13.5.7 Inserting External Source Files 

You can create and edit a source file with any ASCII editor, then import it into a 

project and compile it into individual blocks using this application. To do this, you 

must import the source files into the "Source Files" folder of the S7 program in 

whose S7 user program the blocks created during compilation are to be stored. 

To insert an external source file, proceed as follows: 

1. Select the source file folder of the S7 program in which the external source 

files are to be imported. 

2. Select the menu command Insert > External Source File. 

3. In the dialog box which appears, enter the source file you want to import. 

The file name of the source file you are importing must have a valid file extension. 

STEP 7 uses the file extension to determine the source file type. This means, for 

example, that STEP 7 creates an STL source file when it imports a file with the 

extension .AWL. Valid file extensions are listed in the dialog box under "File Type." 

Note 

You can also use the menu command Insert > External Source File to import 

source files you created with STEP 7 version 1. 


13-16 A5E00706944-01


13.5.8 Generating STL Source Files from Blocks 

You can generate an STL source file which you can edit with any text editor from 

existing blocks. The source file is generated in the source file folder of the S7 

program. 

To generate a source file from a block, proceed as follows: 

1. In the program editor, select the menu command File > Generate Source File. 

2. In the dialog box, select the source file folder in which you want to create the 

new source file. 

3. Enter a name for the source file in the text box. 

4. In the "Select STEP 7 Blocks" dialog box, select the block(s) which you want to 

generate as the given source file. The selected blocks are displayed in the right 

list box. 

5. Confirm with "OK." 

One continuous STL source file is created from the selected blocks and is 

displayed in a window for editing. 

13.5.9 Importing Source Files 

To import a source file from any directory into a project: 

1. In the SIMATIC Manager, select the source file folder into which you want to 

import the source file. 

2. Select the menu command Insert > External Source File. 

3. In the dialog box displayed, select the destination directory and the source file 

to be imported. 

4. Click the "Open" button. 


A5E00706944-01 13-17


13.5.10 Exporting Source Files 

To export a source file from a project to any destination directory: 

1. Select the source file in the source file folder. 

2. Select the menu command Edit > Export Source File in the SIMATIC 

Manager. 

3. Enter the destination directory and file name in the dialog box displayed. 

4. Click the "Save" button. 

Note 

If the object name does not have a file extension, a file extension derived from the 

file type is added to the file name. For example, the STL source file "prog" is 

exported to the file "prog.awl." 

If the object name already has a valid file extension, this is retained and not 

changed. For example, the STL source file "prog.awl" is exported to the file 

"prog.awl." 

If an object name has an invalid file extension (meaning a period is contained in 

the name), no file extension is added. 

You will find a list of valid file extensions in the "Export Source File" dialog box 

under "File type." 


13-18 A5E00706944-01


13.6 Saving and Compiling STL Source Files and Executing 

a Consistency Check 

13.6.1 Saving STL Source Files 

You can save an STL source file at any time in its current state. The program is not 

compiled and no syntax check is run, meaning any errors are saved as well. 

Syntax errors are detected and reported only when the source file is compiled or 

following a consistency check. 

To save a source file under the same name: 

1. Activate the window for the source file you want to save. 

2. Select the menu command File > Save. 

To save a source file under a new name/in another project: 

1. Activate the window for the source file you want to save. 

2. Select the menu command File > Save As. 

3. In the dialog box, select the source file folder in which you want to save the 

source file and enter its new name. 

13.6.2 Checking Consistency in STL Source Files 

Using the menu command File > Consistency Check you can display any syntax 

errors in the STL source file. In contrast to compiling, no blocks are generated. 

When the consistency check is completed, a dialog box is displayed showing you 

the total number of errors found. 

Any errors that are found are listed individually in the lower part of the window with 

a line reference. Correct these errors before compiling the source file so that all the 

blocks can be created. 

13.6.3 Debugging STL Source Files 

The active window for source files is split into two. The following errors are listed in 

the lower half: 

• Errors found after compilation was initiated via menu command File > Compile. 

• Errors found after a consistency check was initiated via menu command File > 

Consistency Check. 

To find the location of an error in a source file, position the cursor on the "Error" tab 

of the message window. The faulty element is automatically highlighted in the code 

section and an error message is output at the status bar. 


A5E00706944-01 13-19


13.6.4 Compiling STL Source Files 

Requirements 

In order to be able to compile the program you created in a source file into blocks, 

the following requirements must be fulfilled: 

• Only source files which are stored in the "Source Files" folder beneath an S7 

program can be compiled. 

• As well as the "Source Files" folder, a "Blocks" folder must also lie beneath the 

S7 program in which the blocks created during compilation can be stored. The 

blocks programmed in the source file are only created if the source file was 

compiled without error. If there are a number of blocks programmed in a source 

file, only those which contain no errors are created. You can then open these 

blocks, edit them, download them to the CPU, and debug them individually. 

Procedure in the Editor 

1. Open the source file you want to compile. The source file must be in the source 

file folder of the S7 program in whose S7 user program the compiled blocks are 

to be stored. 

2. Select the menu command File > Compile. 

3. The "Compiler Report" dialog box is displayed showing the number of lines 

compiled and syntax errors found. 

The blocks specified for the file are only created once the source file has been 

compiled without errors. If there are a number of blocks programmed in a source 

file, only those which contain no errors are created. Warnings of errors do not 

prevent blocks being created. 

Any syntax errors detected during compilation are shown in the lower part of the 

working window and must be corrected before the respective blocks can be 

created. 

Procedure in the SIMATIC Manager 


2. Select one or more source files that you want to compile. You cannot start a 

compilation run for a closed source file folder to compile all the source files in it. 

3. Select the menu command File > Compile to start compilation. The correct 

compiler is called for the source file you selected. The successfully compiled 

blocks are then stored in the block folder beneath the S7 program. 

Any syntax errors detected during compilation are displayed in a dialog box 

and must be corrected so that the blocks where the errors were found can be 

created as well. 


13-20 A5E00706944-01


13.7 Examples of STL Source Files 

13.7.1 Examples of Declaring Variables in STL Source Files 

Variables of Elementary Data Type 

VAR_INPUT 

END_VAR 

VAR_OUTPUT 

END_VAR 

VAR_TEMP 

END_VAR 

// Comments are separated from the declaration section by a double slash. 

// Keyword for input variable 

in1 : INT; // Variable name and type are separated by ":" 

in3 : DWORD; // Every variable declaration is terminated with a semicolon 

in2 : INT := 10; // Optional setting for an initial value in the declaration 

// End declaration of variables of the same declaration type 

// Keyword for output variable 

out1 : WORD; 

// Keyword for temporary variable 

temp1 : INT; 

Variable of Data Type Array 

VAR_INPUT 

END_VAR 

// Input variable 

array1 : ARRAY [1..20] of INT; // array1 is a one-dimensional array 

array2 : ARRAY [1..20, 1..40] of DWORD; // array2 is a two-dimensional array 

Variables of Data Type Structure 

VAR_OUT 

OUTPUT1: 

END_VAR 

// Output variable 

STRUCT // OUTPUT1 has the data type STRUCT 

var1 : BOOL; // Element 1 of the structure 

var2 : DWORD; // Element 2 of the structure 

END_STRUCT; // End of the structure 


A5E00706944-01 13-21


13.7.2 Example of Organization Blocks in STL Source Files 

ORGANIZATION_BLOCK OB1 

TITLE = Example for OB1 with different block calls 

//The 3 networks show block calls 

//with and without parameters 

{S7_pdiag := 'true'} 

AUTHOR 

Siemens 

FAMILY 

Example 

NAME 

Test_OB 

VERSION 1.1 

VAR_TEMP 

Interim value : INT; 

END_VAR 

//System attribute for blocks 

// Buffer 

BEGIN 

NETWORK 

TITLE = Function call transferring parameters 

// Parameter transfer in one line 

CALL FC1 (param1 :=I0.0,param2 :=I0.1); 

NETWORK 

TITLE = Function block call 

// transferring parameters 

// Parameter transfer in more than one line 

CALL Traffic light control , DB6 ( 

// Name of FB, instance data block 

dur_g_p := S5T#10S, // Assign actual values to parameters 

del_r_p := S5T#30S, 

starter 

:= TRUE, 

t_dur_y_car := T 2, 

t_dur_g_ped := T 3, 

t_delay_y_car := T 4, 

t_dur_r_car := T 5, 

t_next_red_car := T 6, 

r_car := "re_main", // Quotation marks show symbolic 

y_car := "ye_main", // names entered in symbol table 

g_car 

:= "gr_main", 

r_ped 

:= "re_int", 

g_ped 

:= "gr_int"); 

NETWORK 

TITLE = Function block call 

// transferring parameters 

// Parameter transfer in one line 

CALL FB10, DB100 (para1 :=I0.0,para2 :=I0.1); 

END_ORGANIZATION_BLOCK 


13-22 A5E00706944-01


13.7.3 Example of Functions in STL Source Files 

FUNCTION FC1: VOID 

// Only due to call 

VAR_INPUT 

param1 : bool; 

param2 : bool; 

END_VAR 

begin 

end_function 

FUNCTION FC2 : INT 

TITLE = Increment number of items 

// As long as the value transferred is < 1000, this function 

// increases the transferred value. If the number of items 

// exceeds 1000, "-1" is returned via the return value 

// for the function (RET_VAL). 

AUTHOR 

Siemens 

FAMILY 

Throughput check 

NAME : INCR_ITEM_NOS 

VERSION : 1.0 

VAR_IN_OUT 

ITEM_NOS : INT; 

END_VAR 

// No. of items currently manufactured 

BEGIN 

NETWORK 

TITLE = Increment number of items by 1 

// As long as the current number of items lies below 1000, 

// the counter can be increased by 1 

L ITEM_NOS; L 1000; 

// Example for more than one 

> I; JC ERR; // statement in a line. 

L 0; T RET_VAL; 

L ITEM_NOS; INC 1; T ITEM_NOS; BEU; 

ERR: L -1; 

T RET_VAL; 

END_FUNCTION 

FUNCTION FC3 {S7_pdiag := 'true'} : INT 

TITLE = Increment number of items 

// As long as the value transferred is < 1000, this function 

//increases the transferred value. If the number of items 

//exceeds 1000, "-1" is returned via the return value 

//for the function (RET_VAL). 

// 

//RET_VAL has a system attribute for parameters here 


A5E00706944-01 13-23


AUTHOR : Siemens 

FAMILY : Throughput check 

NAME : INCR_ITEM_NOS 

VERSION : 1.0 

VAR_IN_OUT 

ITEM_NOS {S7_visible := 'true'}: INT; 

//System attributes for parameters 

END_VAR 

// No. of items currently manufactured 

BEGIN 

NETWORK 

TITLE = Increment number of items by 1 

// As long as the cur rent number of items lies below 1000, 

// the counter can be increased by 1 

L ITEM_NOS; L 1000; 

// Example for more than one 

> I; JC ERR; // statement in a line. 

L 0; T RET_VAL; 

L ITEM_NOS; INC 1; T ITEM_NOS; BEU; 

ERR: L -1; 

T RET_VAL; 

END_FUNCTION 


13-24 A5E00706944-01


13.7.4 Example of Function Blocks in STL Source Files 


TITLE = Simple traffic light switching 

// Traffic light control of pedestrian crosswalk 

// on main street 

{S7_m_c := 'true'} //System attribute for blocks 

AUTHOR : Siemens 

FAMILY : Traffic light 

NAME : Traffic light01 

VERSION : 1.3 

VAR_INPUT 

starter : BOOL := FALSE; // Cross request from pedestrian 

t_dur_y_car : TIMER; // Duration green for pedestrian 

t_next_r_car : TIMER; // Duration between red phases for cars 

t_dur_r_car : TIMER; 

number {S7_server := 'alarm_archiv'; S7_a_type := 'alarm_8'} :DWORD; 

// Number of cars 

// number has system attributes for parameters 

END_VAR 

VAR_OUTPUT 

g_car : BOOL := FALSE; // GREEN for cars_ 

END_VAR 

VAR 

condition : BOOL := FALSE; // Condition red for cars 

END_VAR 

BEGIN 

NETWORK 

TITLE = Condition red for main street traffic 

// After a minimum duration has passed, the request for green at the 

// pedestrian crosswalk forms the condition red 

// for main street traffic. 

A(; 

A #starter; // Request for green at pedestrian crosswalk and 

A #t_next_r_car; // time between red phases up 

O #condition; // Or condition for red 

); 

AN #t_dur_y_car; // And currently no red light 

= #condition; // Condition red 

NETWORK 

TITLE = Green light for main street traffic 

AN #condition; // No condition red for main street traffic 

= #g_car; // GREEN for main street traffic 


A5E00706944-01 13-25


NETWORK 

TITLE = Duration of yellow phase for cars 

// Additional program required for controlling 

// traffic lights 

END_FUNCTION_BLOCK 


VAR_INPUT 

para1 : bool; 

para2: bool; 

end_var 

begin 

end_function_block 

data_block db10 

FB10 

begin 

end_data_block 

data_block db6 

FB6 

begin 

end_data_block 


13-26 A5E00706944-01


13.7.5 Example of Data Blocks in STL Source Files 

Data Block: 


TITLE = DB Example 10 

STRUCT 

aa : BOOL; // Variable aa of type BOOL 

bb : INT; // Variable bb of type INT 

cc : WORD; 

END_STRUCT; 

BEGIN // Assignment of initial values 

aa := TRUE; 

bb := 1500; 

END_DATA_BLOCK 

Data Block with Associated User-Defined Data Type: 


TITLE = DB (UDT) Example 

UDT 20 

// Associated user-defined data type 

BEGIN 

start := TRUE; 

// Assignment of initial values 

setp. := 10; 


Note 

The UDT used must come before the data block in the source file. 


A5E00706944-01 13-27


Data Block with Associated Function Block: 


TITLE = DB (FB) Example 

FB30 

// Associated function block 

BEGIN 

start := TRUE; // Assignment of initial values 

setp. := 10; 


Note 

The associated function block must come before the data block in the source file. 

13.7.6 Example of User-Defined Data Types in STL Source Files 

TYPE UDT20 

STRUCT 

END_STRUCT; 

END_TYPE 

start : BOOL; 

setp. : INT; 

value : WORD; 

// Variable of type BOOL 

// Variable of type INT 

// Variable of type WORD 


13-28 A5E00706944-01

14 Displaying Reference Data 

14.1 Overview of the Available Reference Data 

You can create and evaluate reference data to make it easier to debug and modify 

your user program. You use the reference data for the following: 

• As an overview of your whole user program 

• As the basis for changes and tests 

• To complement your program documentation 

The following table shows which information you can extract from the individual 

views: 

View 

Cross-reference list 

Assignment list for inputs, 

outputs, and bit memory 

Program structure 

Unused symbols 

Addresses without 

symbols 

Purpose 

Overview of the addresses in the memory areas I, Q, M, P, T, C, and DB, 

FB, FC, SFB, SFC calls used in the user program. 

Using the menu command View > Cross References for Address, you 

can display all the cross-references including overlapping access to the 

selected address. 

Overview of which bits of the addresses in the memory areas I, Q, and M, 

and which timers and counters (T and C) are already occupied within the 

user program; forms an important basis for troubleshooting or changes in 

the user program 

Call hierarchy of the blocks within a user program and an overview of the 

blocks used and their nesting levels 

Overview of all symbols which are defined in the symbol table but not used 

in the parts of the user program for which reference data are available 

Overview of all absolute addresses which are used in the parts of the user 

program for which reference data are available but for which no symbol has 

been defined in the symbol table 

The reference data for the selected user program include all the lists in the table. It 

is possible to create and display one or more of the lists for one user program or for 

more than one user program. 


A5E00706944-01 14-1

Displaying Reference Data 

Displaying a Number of Views Simultaneously 

Displaying other lists in additional windows allows you, for example, to: 

• Compare the same lists for different S7 user programs. 

• Display various views of a list, for example, a cross-reference list, displayed 

differently and placed side by side on the screen. You can, for example, display 

only the inputs of an S7 user program in one of the cross-reference lists and 

only the outputs in another list. 

• Open a number of lists for an S7 user program simultaneously, for example, 

program structure and cross-reference list. 

14.1.1 Cross-Reference List 

The cross-reference list provides an overview of the use of addresses within the S7 

user program. 

When you display the cross-reference list you obtain a list of the addresses of 

memory areas input (I), output (Q), bit memory (M), timer (T), counter (C), function 

block (FB), function (FC), system function block (SFB), system function (SFC), I/O 

(P) and data block (DB), as used in the S7 user program along with their addresses 

(absolute address or symbol) and usage. It is displayed in an active window. The 

working window's title bar shows the name of the user program to which the crossreference 

list belongs. 

Every line in the window corresponds to a cross-reference list entry. The search 

function makes it easier for you to find specific addresses and symbols. 

The cross-reference list is the default view when you display reference data. You 

can change this default. 

Structure 

A cross-reference list entry consists of the following columns: 

Column 

Address (symbol) 

Block (symbol) 

Type 

Language 

Location 

Content/Meaning 

Address 

Block in which the address is used 

Whether a read (R) and/or write (W) access to the address is 

involved 

Information on the programming language used to create the block 

Double-click the location field to jump to the location of use for the 

selected address. 

The Block, Type, Language and Location columns are displayed only if the 

corresponding properties were selected for the cross-reference list. This block 

information varies, depending on the programming language the block was written 

in. 

You can set the column width in the cross-reference list shown on the screen as 

required using the mouse. 


14-2 A5E00706944-01


Sorting 

The cross-reference list default option is to sort by memory areas. If you click a 

column header with the mouse, you can sort the entries of this column by the 

default sort criteria. 

Example of Cross-Reference List Layout 

Address (symbol) Block (symbol) Type Language Location 

I1.0 (Motor on) OB2 R STL Nw 2 Inst 33 /0 

M1.2 (MemoryBit) FC2 R LAD Nw 33 

C2 (Counter2) FB2 FBD Nw2 


A5E00706944-01 14-3


14.1.2 Program Structure 

The program structure describes the call hierarchy of the blocks within an S7 user 

program. You are also given an overview of the blocks used, their dependencies, 

and their local data requirements. 

Using the menu command View > Filter in the "Generating Reference Data" 

window you open a tabbed dialog box. In the "Program Structure" tab you can set 

how you want the program structure displayed. 

You can choose between: 

• Call structure and 

• Dependency structure 

Symbols for the Program Structure 

Symbol Meaning 

Block called normally (CALL FB10) 

Block called unconditionally (UC FB10) 

Block called conditionally (CC FB10) 

Data block 

Recursion 

Recursion and called conditionally 

Recursion and called unconditionally 

Block not called 

• Recursions in the call are recognized and indicated graphically in the call 

structure. 

• Recursions within the call hierarchy are indicated by different symbols. 

• Regularly called blocks (CALL), conditionally called blocks (CC) or 

unconditionally called blocks (UC) are marked by different symbols. 

• Blocks not called are displayed at the bottom of the call structure and marked 

with a black cross. There is no further breakdown of the call structure of a block 

which is not called. 


14-4 A5E00706944-01


Call Structure 

The complete call hierarchy is displayed. 

If the program structure is to be created for all organization blocks (OB) and OB1 is 

not in the S7 user program, or if a starting block was specified which is not present 

in the program, you are automatically prompted to specify another block for the 

program structure root. 

Display of multiple calls of blocks can be deactivated by option settings, both for 

the call structure and for the dependency structure. 

Displaying the Maximum Local Data Requirement in the Call Structure 

To give you a quick overview of the local data requirement of the organization 

blocks in the user program displayed, the following can be displayed in the tree 

structure: 

• The maximum local data requirement per OB and 

• The local data requirement per path 

You can activate and deactivate this display in the "Program Structure" tab. 

If synchronous error OBs (OB121, OB122) are present, a plus sign and the 

additional requirement for the synchronous error OBs are displayed after the 

numerical value for the maximum local data requirement. 

Dependency Structure 

The dependency structure shows the dependency of each block in the project on 

other blocks. The block is displayed at the outer left and listed below in the 

indented segments are the blocks that call or use this block. 

Displaying Deleted Blocks 

Lines relating to deleted blocks are highlighted in red color. 


A5E00706944-01 14-5


14.1.3 Assignment List 

The Assignment lists show you which addresses are already assigned in the user 

program. This display is an important basis for troubleshooting or making changes 

in the user program. 

The I/Q/M assignment list display gives you an overview of which bit in which byte 

of the memory areas input (I), output (Q), bit memory (M), times (T) and counter (Z) 

is used. The I/Q/M assignment list is displayed in a working window. 

The working window's title bar shows the name of the S7 user program to which 

the assignment list belongs. 

I/Q/M Table 

Each line contains one byte of the memory area in which the eight bits are coded 

according to their access. It also indicates whether the access is of a byte, word, or 

double word. 

Identification in the I/Q/M Table 

White background 

X 

Blue background 

The address is not accessed and thus not 

assigned. 

The address is accessed directly. 

The address is accessed indirectly (byte, 

word, or double word access). 

Columns in the I/Q/M Table 

Column 

7 

6 

5 

4 

3 

2 

1 

0 

B 

W 

D 


Bit number of the corresponding byte 

The byte is occupied by a one-byte access 

The byte is occupied by a one-word access 

The byte is occupied by a double-word access 


14-6 A5E00706944-01


Example 

The following example shows the typical layout of an assignment list for inputs, 

outputs, and bit memory (I/Q/M). 

The first row shows the assignment of input byte IB 0. Inputs for address IB 0 are 

accessed directly (bit access). The columns "0", "1", "2", "3", "5", and "6" are 

identified with "X" for bit access. 

There is also word access to memory bytes 1 and 2, 2 and 3 or 4 and 5. For this 

reason, a "bar" is shown in the "W" column, and the cells also have a light blue 

background. The black tip of the bar shows the start of word access. 

T/C Table 

Each row displays 10 timers or counters. 

Example 

0 1 2 3 4 5 6 7 8 9 

T 00-09 . T1 . . . T6 . . . 

T 10-19 . . T12 . . . . T17 . T19 

T 20-29 . . . . T24 . . . . . 

Z 00-09 . . Z2 . . . . Z7 . . 

Z 10-19 . . . . . . . . . Z19 

Z 20-29 . . . . . . . . . . 

Z 30-39 . . . . Z34 . . . . . 

In this example, the timers T1, T6, T12, T17, T19, T24 and the counters Z2, Z7, 

Z19, Z34 are occupied. 

The lists are sorted alphabetically. You can arrange the entries by clicking on the 

column title. 


A5E00706944-01 14-7


14.1.4 Unused Symbols 

You are shown an overview of all the symbols with the following characteristics: 

• The symbols defined in the symbol table. 

• The symbols not used in the parts of the user program for which reference data 

exist. 

They are displayed in an active window. The working window's title bar shows the 

name of the user program to which the list belongs. 

Every line shown in the window corresponds to a list entry. A line consists of 

address, symbol, data type, and comment. 

Column 

Address 

Data Type 

Comment 


Absolute address 

Data type of the address 

Comment on the address from the symbol table 

Example of List of Unused Symbols Layout 

Symbol Address Data Type Comment 

MCB1 I 103.6 BOOL Motor circuit breaker 1 



You can sort the entries by clicking the column title. 

You can also remove symbols that are no longer needed from the list. To do this, 

select symbols in the list and then execute the "Delete symbols" function. 


14-8 A5E00706944-01


14.1.5 Addresses Without Symbols 

When you display the list of addresses without symbols, you obtain a list of the 

elements which are used in the S7 user program, but which are not defined in the 

symbol table. They are displayed in an active window. The working window's title 

bar shows the name of the user program to which the list belongs. 

A line consists of the address and the number of times that the address is used in 

the user program. The entries are sorted according to address. 

Example: 

Address 

Number 

Q 2.5 4 

I 23.6 3 

M 34.1 20 

You can also assign names to addresses without symbols. To do this, select 

addresses in the list and then execute the "Edit symbols" function. 

14.1.6 Displaying Block Information for LAD, FBD, and STL 

Language relevant information for Ladder Logic, Function Block Diagram, and 

Statement List is displayed in the cross-reference list and the program structure. 

This information consists of the block language and details. 

The "Program Structure" view only displays language relevant information if the 

filter is set to "Call Structure" in the "Program Structure" tab and if respective 

options were selected. 

Language relevant information in the "Cross References" can be shown or hidden 

via menu command View > Filter. 

• Activate the "Block language" and "Details" check box in the "Cross 

References" tab of the "Filter" dialog box to display the block language 

information. 

Language relevant information varies according to the programming language the 

block was written in and is shown using abbreviations. 

Language Network Statement Instruction 

STL Nw Inst / 

LAD 

Nw 

FBD 

Nw 

Nw and Inst specify in which network and in which statement the address is used 

(cross-reference list) or the block is called (program structure). 

Displaying Block Information for the Optional Programming Languages 

The online help topics on block information can be accessed if the corresponding 

optional package is installed. 


A5E00706944-01 14-9


14.2 Working with Reference Data 

14.2.1 Ways of Displaying Reference Data 

The following possibilities are available for displaying reference data: 

Displaying from the SIMATIC Manager 

1. In the project window in the component view offline, select the "Blocks" folder. 

2. Select the menu command Options > Reference Data > Display. 

Displaying from the Editor Window 

1. Open a block in the "Blocks" folder. 

2. In the window of the programming language editor, select the menu command 

Options > Reference Data. 

The "Customize" dialog box is displayed. Here you can select the view that is 

shown first. The default view is the one in the application for displaying reference 

data that was closed last. You can suppress the dialog for future calls. 

Displaying Directly from the Compiled Block 

You can display the reference data for a compiled block directly from the language 

editor to get a current overview of your user program. 

14.2.2 Displaying Lists in Additional Working Windows 

Using the menu command Window > New Window you can open additional 

working windows and display other views of the reference data (for example, List of 

Unused Symbols). 

You open a working window for previously hidden reference data using the menu 

command Reference Data > Open. 

You can change to another view of the reference data by selecting one of the 

commands in the "View" menu or the corresponding button in the toolbar: 

Reference Data View 

Addresses Without Symbols 

Unused Symbols 

Assignment 

Program Structure 

Cross-Reference List 

Menu Command to Display this Reference Data View 

View > Addresses Without Symbols 

View > Unused Symbols 

View > Assignment 

View > Program Structure 

View > Cross References 


14-10 A5E00706944-01


14.2.3 Generating and Displaying Reference Data 

Generating Reference Data: 

1. In the SIMATIC Manager, select the block folder for which you want to 

generate reference data. 

2. Select the menu command Options > Reference Data > Generate in the 


Before generating reference data, the computer checks to see if any reference data 

are available and if so, whether the data are current. 

• If reference data are available, they are generated. 

• If the reference data available are not current, you can choose whether to 

update the reference data or whether to generate them again completely. 

Displaying Reference Data: 

Using the menu command Options > Reference Data > Display you can display 

the reference data. 

Before displaying reference data, a check is made to ascertain whether any 

reference data exist and whether the existing reference data are current. 

• If no reference data exist they are generated. 

• If incomplete reference data exist, a dialog box is displayed showing a notice 

that the reference data are inconsistent. You can then decide whether you want 

to update the reference data and to what extent. You then have the following 

possibilities: 

Choice 

For modified blocks only 

For all blocks 

Do not update 

Meaning 

The reference data are updated for any modified or new blocks; information 

on any blocks deleted is removed from the reference database. 

The reference data are generated again from scratch for all blocks. 

The reference data are not updated. 

In order to update the reference data, the blocks are recompiled. The appropriate 

compiler is called to compile each block. Using the menu command View > 

Update you can refresh the view of the reference data already displayed in the 

active window. 


A5E00706944-01 14-11


14.2.4 Finding Address Locations in the Program Quickly 

You can use reference data to position the cursor at different locations of an 

address in the program when programming. To do this, you must have up-to-date 

reference data. However, you do not have to start the application for displaying 

reference data. 


1. Select the menu command Options > Reference Data > Generate in the 

SIMATIC Manager to generate the current reference data. This step is only 

necessary if there are no reference data, or if you have old reference data. 

2. Select the address in an open block. 

3. Select the menu command Edit > Go To > Instance. 

A dialog box is now displayed containing a list with all instances of the address 

in the program. 

4. Select the option "Overlapping access to memory areas" if you also want to 

display the instances of addresses whose physical addresses or address area 

overlap with that of the called address. The "Address" column is added to the 

table. 

5. Select a location in the list and click the "Go To" button. 

If the reference data are not up-to-date when you open the dialog box, a message 

to this effect will appear. You can then update the reference data. 

List of Locations 

The list of locations in the dialog box contains the following details: 

• The block in which the address is used 

• The symbolic name of the block, if one exists 

• Details, for example, information on the location and, if appropriate, the 

instruction, which depends on the original programming language of the block 

or source file (SCL) 

• Language-dependent information 

• Type of access to the address: read-only (R), write-only (W), read and write 

(RW), unknown (?). 

• Block language 

You can filter the display of locations and in this way view, for example, write 

access only for an address. The online help for this dialog box provides you with 

more detailed information on what to enter in the fields and the other information 

displayed. 

Note 

Reference data only exist offline. This function therefore always works with the 

cross references of the offline blocks, even if you call the function in an online 

block. 


14-12 A5E00706944-01


14.2.5 Example of Working with Address Locations 

You want to determine at which locations output Q1.0 (direct/indirect) is set. The 

following STL code in OB1 is used as an example: 

Network 1: ........... 

A Q 1.0 // irrelevant 

= Q 1.1 // in this example 

Network 2: 

A M1.0 

A M2.0 

= Q 1.0 // assignment 

Network 3: 

//comment line only 

SET 

= M1.0 // assignment 

Network 4: 

A I 1.0 

A I 2.0 

= M2.0 // assignment 

This results in the following assignment tree for Q1.0: 

 

 

 

 

 

 


A5E00706944-01 14-13


Then proceed as follows: 

1. Position the cursor on Q1.0 (NW 1, Inst 1) in OB1 in the LAD/STL/FBD Editor. 

2. Select the menu command Edit > Go To > Location or use the right mouse 

button to select "Go to Location." 

The dialog box now displays all the assignments for Q1.0: 

OB1 Cycle Execution NW 2 Inst 3 /= W STL 

OB1 Cycle Execution NW 1 Inst 1 /A R STL 

3. Jump to "NW 2 Inst 3" in the Editor using the "Go To" button in the dialog box: 

Network 2: 

A M1.0 

A M2.0 

= Q 1.0 

4. The assignments to both M1.0 and M2.0 must now be checked. First position 

the cursor on M1.0 in the LAD/STL/FBD Editor. 

5. Select the menu command Edit > Go To > Location or use the right mouse 

button to select "Go to Location." The dialog box now displays all the 

assignments for M1.0: 

OB1 Cycle Execution NW 3 Inst 2 /= W STL 

OB1 Cycle Execution NW 2 Inst 1 /A R STL 

6. Jump to "NW 3 Inst 2" in the Editor using the "Go To" button in the dialog box. 

7. In the LAD/STL/FBD Editor in Network 3, you will see the assignment to M1.0 

is not important (because it is always TRUE) and that the assignment to M2.0 

needs to be examined instead. 

In STEP 7 versions earlier than V5, you would now have to run through 

the entire sequence of assignments all over again. The buttons ">>" and 

"


12. Jump to "NW 4 Inst 3" in the LAD/STL/FBD Editor using the "Go To" button: 

Network 4: 

A I 1.0 

A I 2.0 

= M2.0 

13. Now you have to check the assignments to I1.0 and I2.0. This process is not 

described in this example, because you proceed in the same way as before 

(point 4 onwards). 

By switching between the LAD/STL/FBD Editor and the address locations dialog 

box, you can find and check the relevant locations in your program. 


A5E00706944-01 14-15



14-16 A5E00706944-01

15 Checking Block Consistency and Time 

Stamps as a Block Property 

15.1 Checking Block Consistency 

Introduction 

If the interfaces or the code of individual objects have to be adapted or extended, 

this can lead to time stamp conflicts. Time stamp conflicts can in turn cause block 

inconsistencies between calling objects and called objects or reference blocks and 

thus to a high amount correction work. 

The "Check block consistency" function eliminates a lot of this correction work. The 

"Check block consistency" function removes a large part of all the time stamp 

conflicts and block inconsistencies. In the case of objects whose block 

inconsistencies could not be eliminated automatically, the function places you at 

the position to be changed in the corresponding editor, where you can carry out the 

required changes. All the block inconsistencies are eliminated and the objects are 

compiled step-by-step. 

Requirements 

It is only possible to check block consistency for projects created from STEP 7 

V5.0, Service Pack 3. For older projects, you must first compile everything when 

starting the block consistency check (menu command Program > Compile All). 

For objects created with an options package, the options package must be installed 

for the consistency check. 


A5E00706944-01 15-1

Checking Block Consistency and Time Stamps as a Block Property 

Starting the Block Consistency Check 

At the start of the block consistency check, the time stamps of the block interfaces 

are checked, and objects that could cause block inconsistencies are highlighted in 

the tree view (Dependency Tree: References / Call Tree). 

1. In the SIMATIC Manager, go to the project window, select the required block 

folder and then initiate the block consistency via menu command Edit > Check 

Block Consistency. 

2. In "Check Block Consistency" select the menu command Program > Compile 

STEP 7 automatically recognizes the programming language for the relevant 

objects and calls the corresponding editor. As far as possible, the time stamp 

conflicts and block inconsistencies are corrected automatically and the objects 

are compiled. If the time stamp conflict or the inconsistency in an object cannot 

be eliminated automatically, an error message appears in the output window 

(refer to Step 3 for further procedures). This process is repeated automatically 

for all the objects in the tree view. 

3. If it was not possible to eliminate all the block inconsistencies automatically 

during the compilation run, the corresponding objects are marked in the output 

windows as error messages. Position the mouse on the corresponding error 

entry and use the right-hand mouse to call the error display in the pop-up 

menu. The relevant error is opened and the program jumps to the positions to 

be changed. Eliminate all the block inconsistencies, and save and close the 

object. Repeat this process for all the objects marked as errors. 

4. Start Steps 2 and 3 again. Repeat this process until no more errors are 

displayed in the message window. 


15-2 A5E00706944-01


15.2 Time Stamps as a Block Property and Time Stamp 

Conflicts 

Blocks contain a code time stamp and an interface time stamp. These time stamps 

are displayed in the dialog box for the block properties. You can monitor the 

consistency of STEP 7 programs using time stamps. 

STEP 7 displays a time stamp conflict if it detects a violation of the rules when 

comparing time stamps. The following violations may occur: 

• A called block is more up-to-date than the calling block (CALL) 

• A referenced block is more up-to-date than the block which is using it 

• Examples of the second type of violation: 

• A UDT is more up-to-date than the block which is using it; that is, a DB or 

another UDT, or an FC, an FB, or an OB which is using the UDT in the variable 

declaration table. 

• An FB is more up-to-date than its corresponding instance DB. 

• An FB2 is defined as a multiple instance in FB1 and FB2 is more up-to-date 

than FB1. 

Note 

Even if the relationship between the interface time stamps is correct, 

inconsistencies may occur: 

• The definition of the interface for the referenced block does not match the 

definition in the location at which it is used. 

These inconsistencies are known as interface conflicts. They can occur, for 

example, when blocks are copied from different programs or when an ASCII 

source file is compiled and not all of the blocks in a program are generated. 


A5E00706944-01 15-3


15.3 Time Stamps in Logic Blocks 

Code Time stamp 

The time and date the block was created is entered here. The time stamp is 

updated: 

• When the program code is changed 

• When the interface description is changed 

• When the comment is changed 

• When an ASCII source file is created for the first time and compiled 

• When the block properties ("Properties" dialog box) are changed 

Interface Time stamp 

The time stamp is updated: 

• When the interface description is changed (changes to data types or initial 

values, new parameters) 

• When an ASCII source file is created for the first time and compiled, if the 

interface is changed structurally. 

• The time stamp is not updated: 

• When symbols are changed 

• When comments in the variable declaration are changed 

• When changes are made in the TEMP area 

Rules for Block Calls 

• The interface time stamp of the called block must be older than the code time 

stamp of the calling block. 

• Only change the interface of a block if no block is open which calls this block. 

Otherwise, if you save the calling blocks later than the changed block, you will 

not recognize this inconsistency from the time stamp. 

Procedure if a Time stamp Conflict Occurs 

A time stamp conflict is displayed when the calling block is opened. After making 

changes to an FC or FB interface, all calls to this block in calling blocks are shown 

in expanded form. 

If the interface of a block is changed, all blocks which call this block must be 

adjusted as well. 

After making changes to an FB interface, the existing multiple instance definitions 

and instance data blocks must be updated. 


15-4 A5E00706944-01


15.4 Time Stamps in Shared Data Blocks 



• When an ASCII source file is created for the first time 

• When an ASCII source file is compiled 

• When changes are made in the declaration view or in the data view of the block 



• When the interface description is changed in the declaration view (changes to 

data types or initial values, new parameters) 

15.5 Time Stamps in Instance Data Blocks 

An instance data block saves the formal parameters and static data for function 

blocks. 


The time and date the instance data blocks were created is entered here. The time 

stamp is updated when you enter actual values in the data view of the instance 

data block. The user cannot make changes to the structure of an instance data 

block because the structure is derived from the associated function block (FB) or 

system function block (SFB). 


When an instance data block is created, the interface time stamp of the associated 

FB or SFB is entered. 

Rules for Opening Without Conflicts 

The interface time stamps of the FB/SFB and the associated instance data block 

must match. 


If you change the interface of an FB, the interface time stamp of the FB is updated. 

When you open an associated instance data block, a time stamp conflict is 

reported because the time stamps of the instance data block and the FB no longer 

match. In the declaration section of the data block the interface is displayed with 

the symbols generated by the compiler (pseudo-symbols). The instance data block 

can now only be viewed. 

To remedy time stamp conflicts of this type, you must create the instance data 

block for a changed FB again. 


A5E00706944-01 15-5


15.6 Time Stamps in UDTs and Data Blocks Derived from 

UDTs 

User-defined data types (UDTs) can, for example, be used to create a number of 

data blocks with the same structure. 


The code time stamp is updated on every change. 


The interface time stamp is updated when the interface description is changed 

(changes to data types or initial values, new parameters). 

The interface time stamp of a UDT is also updated when the ASCII source file is 

compiled. 

Rules for Opening Without Conflicts 

• The interface time stamp of the user-defined data type must be older than the 

interface time stamp in logic blocks in which this data type is used. 

• The interface time stamp of the user-defined data type must be identical to the 

time stamp of a data block derived from a UDT. 

• The interface time stamp of the user-defined data type must be younger than 

the time stamp of a secondary UDT. 


If you change a UDT definition that is used in a data block, function, function block, 

or another UDT definition, STEP 7 reports a time stamp conflict when the block is 

opened. 

The UDT component is shown as a fanned-out structure. All variable names are 

overwritten by values preset by the system. 

15.7 Correcting the Interfaces in a Function, Function 

Block, or UDT 

If you need to correct the interface in an FB, FC, or UDT, proceed as follows to 

avoid time stamp conflicts: 

1. Generate an STL source file from the block you want to change and all directly 

or indirectly referenced blocks. 

2. Save the changes in the source file you generated. 

3. Compile the modified source file back into blocks. 

You can now save/download the interface changes. 


15-6 A5E00706944-01


15.8 Avoiding Errors when Calling Blocks 

STEP 7 Overwrites Data in the DB Register 

STEP 7 modifies the registers of the S7-300/S7-400 CPU when various 

instructions are executed. The contents of the DB and DI registers are, for 

example, swapped when you call an FB. This allows the instance DB of the called 

FB to be opened without losing the address of the previous instance DB. 

If you work with absolute addressing, errors can occur accessing data saved in the 

registers. In some cases, the addresses in the register AR1 (address register 1) 

and in the DB register are overwritten. This means that you could read or write to 

the wrong addresses. 

! 

Danger 

Danger of damage to property and persons when: 

1. Using CALL FC, CALL FB, CALL multiple instance 

2. Accessing a DB using the complete absolute address (for example 

DB20.DBW10) 

3. Accessing variables of a complex data type 

It is possible that the contents of DB registers (DB and DI), address registers (AR1, 

AR2), and accumulators (ACCU1, ACCU2) may be changed. 

In addition, you cannot use the RLO bit of the status word as an additional (implicit) 

parameter when you call an FB or FC. 

When using the programming techniques mentioned above, you must make sure 

that you save and restore the contents yourself; otherwise errors may occur. 

Saving Correct Data 

The contents of the DB register can cause critical situations if you access the 

absolute addresses of data using the abbreviated format. If, for example, you 

assume that DB20 is open (and that its number is saved in the DB register), you 

can specify DBX0.2 to access the data in bit 2 of byte 0 of the DB whose address 

is entered in the DB register (in other words DB20). If, however, the DB register 

contains a different DB number you access the wrong data. 

You can avoid errors when accessing data of the DB register by using the following 

methods to address data: 

• Use the symbolic address 

• Use the complete absolute address (for example DB20.DBX0.2) 

If you use these addressing methods, STEP 7 automatically opens the correct DB. 

If you use the AR1 register for indirect addressing, you must always load the 

correct address in AR1. 


A5E00706944-01 15-7


Situations in which Registers are Modified 

The manipulation of the address registers for indirect addressing is relevant only in 

STL. The other languages do not support indirect access to the address registers. 

The adaptation of the DB register by the compiler must be taken into account in all 

programming languages to ensure correct parameter transfer when blocks are 

called. 

The contents of the address register AR1 and the DB register of the calling block 

are overwritten in the following situations: 

Situation 

With actual parameters from 

a DB 

When calling blocks in 

conjunction with higher data 

types 

When accessing 

components of a higher data 

type 

Description 

• Once you have assigned an actual parameter to a block from a DB 

(for example DB20.DBX0.2) STEP 7 opens the DB (DB20) and 

adapts the content of the DB register. The program then works with 

the adapted DB after the block call. 

• After a block has been called from within an FC that transfers a 

component of a formal parameter of a higher data type (string, array, 

structure or UDT) to the called block, the content of AR1 and the DB 

register of the calling block are modified. 

• The same applies to a call from within an FB if the parameter is in the 

VAR_IN_OUT area of the caller. 

• When an FB accesses a component of a formal parameter of a 

higher data type in the VAR_IN_OUT area (string, array, structure or 

UDT), STEP 7 uses the address register AR1 and the DB register. 

This means that the contents of both registers are modified. 

• When an FC accesses a component of a formal parameter of a 

higher data type in the VAR_IN_OUT area (string, array, structure or 

UDT), STEP 7 uses the address register AR1 and the DB register. 

This means that the contents of both registers are modified. 

Note 

• When an FB is called from within a version 1 block, the actual parameter for 

the first Boolean IN or IN_OUT parameter is not transferred correctly if the 

command before the call does not limit the RLO. In this case, it is logically 

combined with the existing RLO. 

• When an FB is called (single or multiple instance), the address register AR2 is 

written to. 

• If the address register AR2 is modified in an FB, such by the operations UC, 

CC or CALL (Call FC/SFC without parameters), there is no guarantee that the 

FB will be executed correctly. 

• If the complete absolute DB address is not transferred to an ANY parameter, 

the ANY pointer does not get the DB number of the open DB. Instead, it 

always gets the number 0. 


15-8 A5E00706944-01

16 Configuring Messages 

16.1 The Message Concept 

Messages allow you to detect, localize, and remedy errors during processing on 

the programmable controllers quickly, thus reducing downtimes on a plant 

considerably. 

Before messages can be output, they must first be configured. 

With STEP 7, you can create and edit messages linked to events with assigned 

message texts and message attributes. You can also compile the messages and 

display them on display devices. 

16.1.1 What Are the Different Messaging Methods? 

There are different methods of creating messages. 

Bit Messaging 

Bit messaging requires the programmer to perform three steps: 

• Create the user program on the programming device and set the required bit. 

• Create an assignment list using any text editor in which a message text is 

assigned to the message bit (for example, M 3.1 = limit switch pressure). 

• Create the list of message texts on the operator panel on the basis of the 

assignment list. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The operator interface system queries the programmable controller cyclically to see 

whether the message bit has changed or not. If the programmable controller 

signals a change, the corresponding message is displayed. The message receives 

the time stamp from the operator interface system. 


A5E00706944-01 16-1

Configuring Messages 

Message Numbering 

Message numbering requires the programmer to perform only one step: 

• Create the user program on the programming device, set the required bit, and 

assign the required message text to the bit directly while programming. 

 

 

 

 

 

 

 

 

 

 

 

There is no cyclic query of the programmable controller. When the programmable 

controller signals a change, the corresponding message number is passed to the 

operator interface system and the corresponding message text is displayed. The 

message receives the time stamp from the programmable controller and can 

therefore be traced more exactly than with bit messaging. 


16-2 A5E00706944-01


16.1.2 Choosing a Messaging Method 

Overview 

The following table shows the properties and requirements for the different 

messaging methods: 

Message Numbering 

• Messages are managed in a common 

database for programming device and 

operator panel 

• The load on the bus is low (programmable 

controller signals active) 

• Messages receive the timestamp from the 


Bit Messaging 

• There is no common database for 

the programming device and 

operator panel 

• The load on the bus is high 

(operator panel polls) 

• Messages receive the timestamp 

from the operator panel 

The message numbering method recognizes the following three types of 

messages: 

Block-Related Messages Symbol-Related Messages User-Defined Diagnostic 

Messages 

• Synchronous to the 

program 

• Display using WinCC and 

ProTool (ALARM_S only) 

• Possible with S7-300/400 

• Program by using message 

blocks: 

- ALARM 

- ALARM_8 

- ALARM_8P 

- NOTIFY 

- NOTIFY_8P 

- ALARM_S(Q) 

- AR_SEND 

- ALARM_D(Q) 

• Transfer to the operator 

panel 

- for WinCC via AS-OS 

connection 

configuration 

- for ProTool via ProTool 

functions 

• Asynchronous to the 

program 

• Display using WinCC 

• Possible only with S7-400 

• Configure via the symbol 

table 

• Download to the PLC via 

system data blocks (SDBs) 

• Transfer to the operator 

panel via AS-OS connection 

configuration 

• Synchronous to the program 

• Display in the diagnostic buffer 

on the programming device 

• Possible with S7-300/400 

• Program using message block 

(system function) 

- WR_USMSG 

• No transfer to the operator 

panel 

STEP 7 only supports the more user-friendly message numbering method which 

will be described in detail below. Bit messaging is configured in the HMI devices 

and is described there. 


A5E00706944-01 16-3


Examples of Message Numbering 

Messaging Method 

Block-related messages 

Symbol-related messages 

User-defined messages 

Application 

Used to report program-synchronous events, for example, to 

show that a controller has reached a limit value 

Used to report events that are independent of the program, 

for example, a switch setting being monitored 

Used to report diagnostic events in the diagnostic buffer, with 

each call of the SFC 


16-4 A5E00706944-01


16.1.3 SIMATIC Components 

Overview 

The following figure shows an overview of which SIMATIC components are 

involved in configuring and displaying messages. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

16.1.4 Parts of a Message 

How a message is displayed depends on the messaging method, the message 

block used, and the display device. 

The possible parts of a message are listed in the following table: 

Part 

Timestamp 

Message state 

Associated value 

Image 

Message number 

Message texts 

Description 

Generated in the programmable controller when the message event 

occurs 

The following states are possible: incoming, outgoing, outgoing 

without acknowledgement, outgoing with acknowledgement 

Some messages can be assigned a process value that can be 

evaluated by the message block used 

If the system crashes the messages that occurred can be displayed 

subsequently on the operator station 

A unique number throughout the project or CPU (project-oriented or 

CPU-oriented). The number is assign by the system and identifies a 

message 

Configured by the user 


A5E00706944-01 16-5


Example 

The following example shows an alarm message on an operator panel. 

 

 

 

 

 

 

 

16.1.5 Which Message Blocks Are Available? 

You can choose between the following message blocks, each of which contains a 

programmed message function: 

• SFB 33: "ALARM" 

• SFB 34: "ALARM_8" 

• SFB 35 "ALARM_8P" 

• SFB 36 "NOTIFY" 

• SFC 18: "ALARM_S" and SFC 17: "ALARM_SQ" 

• SFB 37: "AR_SEND" (for sending archives; no configuration of message texts 

and message attributes possible) 

• SFB 31: "NOTIFY_8P" 

• SFC 107: "ALARM_DQ" 

• SFC 108: "ALARM_D" 

Details are found in the reference online help on blocks. 

When to Use Which Message Block 

The following table helps you decide which message block to choose for your 

particular task. Selecting a message block depends on: 

• The number of channels available in the block and therefore the number of 

signals that are monitored with each block call 

• Whether messages are to be acknowledged 

• The option of also specifying associated values 

• The display devices to be used 

• The project data for the CPU to be used. 


16-6 A5E00706944-01


Message 

Block 

ALARM 

SFB33 

ALARM_8 

SFB34 

ALARM_8P 

SFB35 

NOTIFY 

SFB36 

NOTIFY_8P 

SFB 31 

AR_SEND 

SFB37 

ALARM_SQ 

SFC17 

ALARM_S 

SFC18 

ALARM_DQ 

SFC 107 

ALARM_D 

SFC 108 

Channels 

Acknowledgement 

Associated 

Values 

1 Possible Up to 

10 

WinCC 

Display 

ProTool 

Display 

CPU 

Messages 

/S7 Status 

Display 

PLC 

Remarks 

Yes No No S7-400 Sends a 

message for 

each incoming 

or outgoing 

edge 

8 Possible No Yes No No S7-400 Sends a 

message for 

each incoming 

or outgoing 

edge of one or 

more signals 

8 Possible Up to Yes No No S7-400 As ALARM_8 

10 

1 No Up to Yes No No S7-400 As ALARM 

10 

8 No up to Yes No No S7-400 As NOTIFY 

10 

1 Yes No No S7-400 Used to send 

an archive; no 

configuration of 

message texts 

and message 

attributes 

possible 

1 Possible 1 Yes Yes* Yes S7-300/ 

S7-400 

1 No 1 Yes Yes* Yes S7-300/ 

S7-400 

1 Possible 1 Yes Yes Yes S7- 

300/400 

1 No 1 Yes Yes Yes S7- 

300/400 

* depending on the OP type 

Not an edge 

change but 

every SFC call 

generates a 

message 

As ALARM_SQ 

As ALARM_SQ 

As ALARM_SQ 


A5E00706944-01 16-7


16.1.6 Formal Parameters, System Attributes, and Message Blocks 

Formal Parameters as Message Number Inputs 

For each message or group of messages you need a formal parameter in your 

program that you specify as the IN parameter in the variable overview of your 

program. This formal parameter is then used as a message number input and 

forms the basis of a message. 

How to Provide Formal Parameters with System Attributes 

As a prerequisite for starting message configuration, you must first provide the 

formal parameters with system attributes as follows: 

1. Add the following system attributes for parameters: "S7_server" and 

"S7_a_type" 

2. Assign values to the system attributes corresponding to the message blocks 

that you called in your program code. The value for "S7_server" is always 

"alarm_archiv", the value for "S7_a_type" corresponds to the called message 

block. 

System Attributes and Corresponding Message Blocks 

The message blocks themselves are not displayed as objects in the message 

server; instead, the display contains the corresponding values of the system 

attribute "S7_a_type". These values have the same names as the message blocks 

that exist as SFBs or SFCs (exception: "alarm_s"). 

S7_a_type Message Description Properties 

Block 

alarm_8 ALARM_8 SFB34 8 channels, can be acknowledged, no 

associated values 

alarm_8p ALARM_8P SFB35 8 channels, can be acknowledged, up to 10 

associated values per channel 

notify NOTIFY SFB36 1 channel, cannot be acknowledged, up to 10 


alarm ALARM SFB33 1 channel, can be acknowledged, up to 10 


alarm_s ALARM_S SFC18 1 channel, cannot be acknowledged, up to 1 

associated value 

alarm_s ALARM_SQ SFC17 1 channel, can be acknowledged, up to 1 


ar_send AR_SEND SFB37 Used to send an archive 

notify_8p NOTIFY_8P SFB 31 8 channels, cannot be acknowledged, up to 10 


alarm_s ALARM_DQ SFC 107 1 channel, cannot be acknowledged, up to 1 


alarm_s ALARM_D SFC 108 1 channel, cannot be acknowledged, up to 1 


You will find more detailed information in the reference online help on system 

attributes. 

The system attributes are assigned automatically if the message blocks that you 

use in your program are SFBs or FBs with corresponding system attributes and are 

called as multiple instances. 


16-8 A5E00706944-01


16.1.7 Message Type and Messages 

Message configuration allows you to use different procedures to create a message 

type or a message. This depends on the message-type block via which you gain 

access to message configuration. 

The message-type block can be either a function block (FB) or an instance data 

block. 

• With an FB you can create a message type to use as a type for creating 

messages. All entries you make for the message type are entered in the 

messages automatically. If you assign an instance data block to the function 

block, messages for the instance data block are generated automatically in 

accordance with the message type and assigned message numbers. 

• For an instance data block, you can modify messages generated based on this 

message type for a specific instance. 

The visible difference here is that message numbers are assigned for messages 

but not for message types. 

Locking Data for a Message Type 

Message configuration allows you to enter texts and attributes for event-dependent 

messages. You can also specify, for example, how you want to display the 

messages on specific display devices. To make it easier to generate messages, 

you can work with message types. 

• When you enter data (attributes and texts) for the message type, you can 

specify whether they are to be locked or not. With locked attributes a key 

symbol is added next to the input box or a checkmark is placed in the "Locked" 

column. Locked texts show a checkmark in the "Locked" column. 

• With the message type "locked data" you cannot make changes in the instancespecific 

messages. The data are only displayed. 

• If you do need to make changes, you must go back to the message type, 

remove the lock, and make the changes there. The changes do not apply for 

instances that were generated before the change. 

Modifying Data Of Message Types 

Whether or not the modification of data at message types has an influence on the 

instances depends on whether you have assigned message numbers globally to 

the project (project-oriented message numbers) or to the CPU (CPU-oriented 

message numbers) when you generated your project. 

• Assigning project-oriented message numbers: When you subsequently modify 

message type data you also want to apply to the instances, you must also 

modify data at the instances accordingly. 


A5E00706944-01 16-9


• Assigning CPU-oriented message numbers: Subsequent modifications of 

message type data are automatically applied at the instances. 

Exceptions: You have previously modified data at the instance or have 

subsequently locked or unlocked message type data. If you copy an FB and an 

instance DB from a project with project-oriented message numbers to a project 

with CPU-oriented message numbers, you will then have to change the data at 

the instance in the same way you did it at the message type. 

Caution: 

• When you copy the instances to another program and do not include the 

message type, the instance might only be partially displayed. To remedy, copy 

the message type to the new program. 

• If texts and attributes for an instance are displayed in green, this means the 

following: these texts and attributes are still as they were configured in the 

message type. They have not been changed at the instance. 

16.1.8 How to Generate an STL Source File from Message-Type Blocks 

When you generate an STL source file from message-type blocks, the 

configuration information is also written to the source file. 

This information is written to a pseudo-comment that begins with 

"*$ALARM_SERVER" and ends with "*". 

Caution 

When you set a symbolic reference for a block, note that the symbol table may not 

be modified prior to the compilation of the source file. 

When the source file contains multiple blocks, several pseudo-comment blocks will 

be joined to form a single comment block. Individual blocks with message attributes 

must not be deleted from the STL source file. 

16.1.9 Assigning Message Numbers 

You can specify if you want to assign message numbers for the project (projectoriented 

message numbers) or for the CPU (CPU-oriented message numbers). 

Assigning message numbers for the CPU has the advantage of allowing you to 

copy a program without having the message numbers change, in which case they 

would have to be recompiled. It is only possible to display message numbers for 

the CPU on an HMI device with the applications "WinCC V6.0" and/or "ProTool 

V6.0". If you are working with an earlier version of these applications, you have to 

select message numbers for the project. 


16-10 A5E00706944-01


16.1.10 Differences Between Project-Oriented and CPU-Oriented 

Assignment of Message Numbers 

The table below lists the differences between project-oriented and CPU-oriented 

assignment of message numbers: 

Project oriented 

CPU oriented 

Some of the message attributes and texts 

depend on the used HMI unit and must be 

configured display specific. 

Programs must be recompiled after they have 

been copied. 

When you subsequently change message 

type data (texts and attributes), you must also 

modify the instances. 

Texts can only be written on one line. 

The assigned attributes and texts do not depend on the 

HMI unit used, that is, there is no need to enter further 

display devices or specify a display specific message for 

this device. 

Programs can be copied to other locations of a project 

and to other projects (cross-project copying). However, 

the program must be recompiled if only single blocks 

have been copied. 

If you subsequently change message type data (texts 

and attributes), all changes are applied automatically to 

the instances (Exception: you have previously changed 

the data of the instance). 

Texts can be written on several lines. 

16.1.11 Options for Modifying the Message Number Assignment of a 

Project 

In the "Message number" tab of the SIMATIC manager you can preset the way 

message numbers will be assigned (Menu command Options > Customize) to 

future projects and libraries. In this tab you determine whether the message 

numbers are to be assigned only to the CPU (CPU-oriented) or only to the project 

(project-oriented). You can also choose "Always ask for setting" if you want to 

specify the assignment later. 

If the initially set default "CPU-oriented" or "project-oriented" was active when you 

created the project or library, you can no longer change the type of message 

number assignment for this project or library. 

If you have set "project-oriented" unique message number assignment and want to 

set "CPU-oriented" unique assignment proceed as follows: 

1. In SIMATIC Manager, select the corresponding project or library. 

2. Select menu command File > Save As. 

3. Enable the "With rearrangement" check box In the next dialog box and enter a 

new name. 

4. Start the process with "Save As" and confirm your entries with "OK". 

5. In one of the next dialogs you can specify "CPU-oriented" unique message 

number assignments. 

You can use the File > Delete command to delete the original project or library. 

Differences Between Project-Oriented and CPU-Oriented Assignment of Message 

Numbers 


A5E00706944-01 16-11


16.2 Project-Oriented Message Configuration 

16.2.1 How to Assign Project-Oriented Message Numbers 

Messages are identified by a number which is unique throughout a project. To 

achieve this, the individual STEP 7 programs are each allocated a number range 

within the total available range (1 to 2097151). If you copy a program and a conflict 

results - that is, if the same message numbers have already been assigned in the 

target range - the new program must be allocated a new number range. If such a 

situation arises, STEP 7 automatically opens the dialog box in which you can 

specify the new number range. 

If no messages have been configured, you can also set or change the number 

range for an S7 program using the menu command Edit > Special Object 

Properties > Message Numbers. 

By default, the message number range is assigned in steps of 20,000. 

16.2.2 Assigning and Editing Block-Related Messages 

Block-related messages are assigned to a block (instance DB). To create a blockrelated 

message, you can use system function blocks (SFBs) and system functions 

(SFCs) as message blocks. 


16-12 A5E00706944-01


16.2.2.1 How to Create Block-Related Messages (Project-Oriented) 


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Programming Message-Type Blocks (FB) 

1. In the SIMATIC Manager select the function block (FB) for which you want to 

generate a block-related message and open this block with a double-click. 

Result: The selected block is opened and displayed in the "LAD/STL/FBD" 

window. 

2. Fill out the variable declaration table. For every message block that is called in 

the function block you must declare variables in the calling function block. 

Enter the following variables in the variable overview column: 

- For the parameter "IN" enter a symbolic name for the message block input, 

for example, "Meld01" (for message input 01) and the data type (must be 

"DWORD" without an initial value). 

- For the parameter "STAT" enter a symbolic name for the message block to 

be called, for example, "alarm" and the corresponding data type, in this 

case "SFB33." 


A5E00706944-01 16-13


3. In the code section of the function block, insert the call for the selected 

message block, here "CALL alarm", and finish your entry with RETURN. 

Result: The input variables for the called message block (here SFB33) are 

displayed in the code section of the function block. 

4. Assign the symbolic name you assigned in step 2 for the message block input, 

here "Mess01," to the variable "EV_ID". The system attributes are now applied 

for the message of type "alarm". 

Result: A flag should appear in the "Name" column for the parameter "IN" if 

the column is not selected. The selected block is then set as a message-type 

block. The required system attributes (for example, S7_server and S7_a_type) 

and the corresponding values are assigned automatically (Note: for certain 

SFCs you will have to assign the system attributes for the parameter "IN" 

yourself. To do this select the menu command Edit > Object Properties and 

then select the "Attributes" tab.). 

Caution: If you do not call an SFB, but rather an FB that contains multiple 

instances and configured messages, you must also configure the messages of 

this FB, with multiple instances, in the calling block. 

5. Repeat steps 2 to 4 for all calls to message blocks in this function block. 

6. Save the block using the menu command File > Save. 

7. Close the "LAD/STL/FBD" window. 

Opening the Message Configuration Dialog Box 

• Select the desired message block and then select the menu command Edit > 

Special Object Properties > Message in the SIMATIC Manager. 

Result: The STEP 7 message configuration dialog box (standard dialog box) is 

opened. Information on opening the PCS7 Message Configuration function can 

be found under PCS 7 Message Configuration. 

Editing a Message Type 

1. Select the desired message block, open the message configuration, and enter 

the required message text in the "Text" and "Attributes" tabs or select the 

required message attributes. 

If you selected a multi-channel message block (for example, "ALARM_8"), you 

can assign specific texts and, to certain extent, specific attributes to each 

subnumber. 

2. Assign the required display devices to the message type by clicking the "New 

Device" button and selecting the required display devices in the "Add Display 

Device" dialog box. 

In the following tabbed pages, enter the required texts and attributes for the display 

devices. Exit the dialog box with "OK". 

Note 

When editing the display device specific texts and attributes, please read the 

documentation supplied with your display device. 


16-14 A5E00706944-01


Creating Instance Data Blocks 

1. When you have created a message type, you can associate instance data 

blocks to it and edit the instance-specific messages for these data blocks. 

To do this, in the SIMATIC Manager open the block that is to call your 

previously configured function block, for example, "OB1", by double-clicking it. 

In the open code section of the OB, enter the call ("CALL"), the name and 

number of the FB to be called and of the instance DB that you want to 

associate with the FB as an instance. Confirm your entry with RETURN. 

Example: Enter "CALL FB1, DB1". If DB1 does not yet exist, confirm the 

prompt asking whether you want the instance DB created with "Yes." 

Result: The instance DB is created. In the code section of the OB, the input 

variables of the associated FBs, here for example "Mess01," and the message 

number allocated by the system, here "1," are displayed. 

2. Save the OB with the menu command File > Save and close the 

"LAD/STL/FBD" window. 

Editing Messages 

1. In SIMATIC Manager, select the generated instance DB, for example, "DB1" 

and then call the menu command Edit > Special Object Properties > 

Message to open the message configuration dialog box. 

Result: The "Message Configuration" dialog box is opened and the selected 

instance DB with the message number allocated by the system is displayed. 

2. Enter the required changes for the corresponding instance DB in the 

appropriate tabs and add other display devices if you wish. Exit the dialog box 

with "OK." 

Result: The message configuration for the selected instance DB is then 

complete. 

Transferring Configuration Data 

• Transfer the configured data to the WinCC database (via the AS-OS connection 

configuration) or the ProTool database. 


A5E00706944-01 16-15


16.2.2.2 How to Edit Block-Related Messages (Project-Oriented) 

1. In the SIMATIC Manager, select a block and then select the menu command 

Edit > Special Object Properties > Message. 

2. In the folder structure, click a message block input or one of its subnumbers (if 

available). 

Result: The tabbed section for a standard message is displayed. 

3. Enter the required texts and attributes in the "Text" and "Attributes" tabs. 

Result: You have created a standard message that can be displayed on all 

display devices. 

4. Using the "New Device" button, add a new display device of the type "ProTool" 

(Opx) or "WinCC." Only those display devices on which the configured 

messages can be displayed are available for selection. 

Result: The new device is added and selected, and the corresponding tabbed 

section is displayed. 

5. Enter attributes and texts for the display-specific message in the displayspecific 

"Texts" and "Attributes" tabs. 

Result: You have created a message variation that is only used as the 

message for the selected display device. 

If you want to edit other message variations for existing display devices: 

• Select and open the message block in the detailed view by double-clicking it. 

Result: The first display device is automatically selected and you can now edit 

display-specific message variations for it. 

16.2.2.3 How to Configure PCS 7 Messages (Project-Oriented) 

For editing message types and messages to be output on WinCC display devices, 

the PCS7 message configuration function in STEP 7 provides a user-friendly 

method of: 

• Simplifying the configuration of display devices (created automatically) 

• Simplifying the entry of attributes and texts for messages 

• Ensuring that messages are standardized. 


16-16 A5E00706944-01


Opening the PCS7 Message Configuration Function 

1. In the SIMATIC Manager, select the block (FB or DB) whose message texts 

you want to edit. Select the menu command Edit > Object Properties to open 

the dialog box for entering system attributes. 

2. In the table shown, enter the system attribute "S7_alarm_ui" and the value: "1" 

(the value 0 disables the PCS7 message configuration tool). Property 

parameters can be set in LAD/STL/FBD. DBs generated afterwards and 

assigned to the corresponding FBs take on these attributes and can be 

switched independently of their message type (FB). 

Note 

A syntax check is performed when you enter the system attributes. Faulty entries 

are highlighted in red. 

3. Exit the dialog box with "OK." 

4. Select the menu command Edit > Special Object Properties > Message 

Result: The "PCS7 Message Configuration" dialog box is opened. 

Editing Message Types 

1. In the SIMATIC Manager, select the FB whose message texts you want to edit, 

and open the PCS7 message configuration dialog box. 

Result: The dialog box displays a tab for each message block for which you 

declared a variable in the FB. 

2. Fill out the text boxes for the message components "Origin," "OS area," and 

"Batch ID." 

3. Enter the message class and the event text for all events of the message 

blocks used and specify whether every event must be acknowledged 

individually. 

4. For the message parts that apply for all instances and should not be changed, 

select the "Locked" check box. 


1. Open SIMATIC Manager. Select the instance DB whose message texts you 

want to edit and open PCS7 message configuration function. 

2. Do not edit instance-specific message parts that are not locked. 


A5E00706944-01 16-17


16.2.3 Assigning and Editing Symbol-Related Messages 

16.2.3.1 How to Assign and Edit Symbol-Related Messages (Project- 

Oriented) 

Symbol-related messages (SCAN) are assigned directly to a signal in the symbol 

table. Permitted signals are all Boolean addresses: inputs (I), outputs (Q), and bit 

memory (M). You can assign these signals different attributes, messages texts, 

and up to 10 associated values with the message configuration function. You can 

make it easier to select signals in the symbol table by setting filters. 

With a symbol related message you can scan a signal in a predefined time interval 

to determine whether a signal change has taken place. 

Note 

The time interval is dependent on the CPU used. 


 

 

 

 

 

 

 

 

During processing, the signals for which you have configured messages are 

checked asynchronously to your program. The checks take place at the configured 

time intervals. The messages are displayed on the assigned display devices. 

Caution 

If you want to assign or edit symbol-related messages and, during the same work 

procedure, you have previously copied symbols between two symbol tables, you 

will then have to first close the symbol table that you no longer need to work in. 

Otherwise, you will not be able to save your message configurations. Under certain 

conditions, the last entries made in the message configuration dialog will be lost. 


16-18 A5E00706944-01


16.2.4 Creating and Editing User-Defined Diagnostic Messages 

Using this function you can write a user entry in the diagnostic buffer and send a 

corresponding message which you create in the message configuration application. 

User-defined diagnostic messages are created by means of the system function 

SFC52 (WR_USMSG; Error Class A or B) which is used as a message block. You 

must insert the call for the SFC52 in your user program and allocate it the event ID. 

Requirements 

Before you can create a user-defined diagnostic message, you must have done the 

following: 

• Created a project in the SIMATIC Manager 

• Created a S7/M7 program in the project to which you want to assign one or 

more messages. 


To create and display a user-defined diagnostic message, proceed as follows: 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 16-19


16.3 CPU-Oriented Message Configuration 

16.3.1 How to Assign CPU-Oriented Message Numbers 

Messages of the CPU are identified by a unique number. This is done by assigning 

each CPU a number area. Other than for assigning project-oriented message 

numbers, there is no need to assign a new number area to the new program. A 

new compilation of the program is therefore not required. Note the exception when 

you copy individual blocks: In this case, you must recompile the program in order to 

implement the modified message number. 

Requirements 

• WinCC V6.0 

• ProTool V6.0 


16-20 A5E00706944-01


16.3.2 Assigning and Editing Block-Related Messages 

16.3.2.1 How to Create Block-Related Messages (CPU-Oriented) 

Principles of operation 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Programming Message-Type Blocks (FB) 

1. In SIMATIC Manager, select the function block (FB) for which you want to 

generate a block-related message and open it with a double-click. 

Result: The selected block is opened and displayed in the "LAD/STL/FBD" 

window. 

2. Fill out the variable declaration table. You must declare the corresponding 

variables in the calling function block for every message block that is called in 

the function block. 

Enter the following variables in the variable overview column: 

- For the parameter "IN" enter a symbolic name for the message block input, 

for example, "Meld01" (for message input 01) and the data type (must be 

"DWORD" without an initial value). 


A5E00706944-01 16-21


- For the parameter "STAT" enter a symbolic name for the message block to 

be called, for example, "alarm" and the corresponding data type, here 

"SFB33." 

3. In the code section of the function block, insert the call for the selected 

message block, here "CALL alarm", and finish your entry with RETURN. 

Result: The input variables for the called message block (here SFB 33) are 

displayed in the code section of the function block. 

4. Assign the symbolic name you assigned in step 2. for the message block input, 

here "Mess01," to the variable "EV_ID". 

Result: A flag should appear in the "Name" column for parameter "IN" if the 

column is not selected. The selected block is then set as a message-type 

block. The required system attributes (for example, S7_server and S7_a_type) 

and the corresponding values are assigned automatically (Note: for certain 

SFCs you will have to assign the system attributes for the parameter "IN" 

yourself. To do this select the menu command Edit > Object Properties and 

then select the "Attributes" tab.). 

Caution: If you call an FB that contains multiple instances and configured 

messages instead of an SFB, you must also configure the messages of this FB 

in the calling block. 

5. Repeat steps 2. to 4. for all calls to message blocks in this function block. 

6. Save the block using the menu command File > Save. 

7. Close the "LAD/STL/FBD" window. 

Opening the Message Configuration Dialog Box 

• Select desired message block and then select the menu command Edit > 

Special Object Properties > Message in the SIMATIC Manager. 

Result: The STEP 7 message configuration dialog box is opened. Information 

on opening the PCS7 Message Configuration function can be found under 

PCS7 Message Configuration (CPU-Oriented). 

Editing a Message Type 

• Select the desired message block. 

• Enter the required text in the appropriate columns or select the required 

attributes. 

In the "Message Configuration" dialog box, you can click on the "More" button 

and enter the message text and additional text in the "Default Texts" tab 

If you selected a multi-channel message block (for example, "ALARM_8"), you 

can assign specific texts and, to certain extent, specific attributes to each 

subnumber. 

• If the texts or attributes for the instance should not be changed, you can lock 

them in the message type. 


16-22 A5E00706944-01


Creating Instance Data Blocks 

1. When you have created a message type, you can associate instance data 

blocks to it and edit the instance-specific messages for these data blocks. 

To do this, in the SIMATIC Manager open the block that is to call your 

previously configured function block, for example, "OB1" by double-clicking it. 

In the open code section of the OB, enter the call ("CALL"), the name and 

number of the FB to be called and of the instance DB that you want to 

associate with the FB as an instance. Confirm your entry with RETURN. 

Example: Enter "CALL FB1, DB1". If DB1 does not yet exist, confirm the 

prompt asking whether you want the instance DB created with "Yes." 

Result: The instance DB is created. In the code section of the OB, the input 

variables of the associated FBs, here for example "Mess01," and the message 

number allocated by the system, here "1," are displayed. 

2. Save the OB with the menu command File > Save and close the 

"LAD/STL/FBD" window. 


1. In the SIMATIC Manager, select the created instance DB, for example, "DB1" 

and select the menu command Edit > Special Object Properties > Message 

to open the message configuration dialog box. 

Result: The "Message Configuration" dialog box is opened and the selected 

instance DB with the message number assigned by the system is displayed. 

2. Enter the required changes for the corresponding instance DB in the 

appropriate tabs and add other display devices if you wish. Exit the dialog box 

with "OK." 

Result: The message configuration for the selected instance DB is then 

complete. 

Note 

If texts and attributes for an instance are displayed in green, this means the 



Transferring Configuration Data 

• Transfer the configured data to the WinCC database (via the AS-OS connection 

configuration) or the ProTool database. 


A5E00706944-01 16-23


16.3.2.2 How to Edit Block-Related Messages (CPU-Oriented) 

1. Select a message block, and then select the menu command Edit > Special 

Object Properties > Message to call message configuration. 

2. Enter your required text in the "Default Texts" and "Additional Texts" columns. 

You can also click on the "More" button and enter your required text (with line 

breaks) in the "Default Texts" and "Additional Texts" dialog boxes. 

Result: You have created a standard message. 

Note 

If texts and attributes for an instance are displayed in green, this means the 




16-24 A5E00706944-01


16.3.2.3 How to Configure PCS 7 Messages (CPU-Oriented) 

For editing message types and messages to be output on WinCC display devices 

(as of V6.0), the PCS7 message configuration function in STEP 7 provides a userfriendly 

method of: 

• Simplifying the configuration of display devices 

• Simplifying the input of attributes and texts for messages 

• Ensuring that messages are standardized. 

Opening the PCS7 Message Configuration Function 

1. In SIMATIC Manager, select the block (FB or DB) whose message texts you 

want to edit. Select the menu command Edit > Object Properties to open the 

dialog box for entering system attributes. 

2. In the table shown, enter the system attribute "S7_alarm_ui" and the value: "1" 

(the value 0 disables the PCS7 message configuration tool). Property 

parameters can be set in LAD/STL/FBD. DBs generated afterwards and 

assigned to the corresponding FBs take on these settings and can be switched 

using their own attribute settings, independently of their message type (FB). 

Note 

A syntax check is performed when you enter the system attributes. Faulty entries 

are highlighted in red. 

3. Exit the dialog box with "OK." 

4. Select the menu command Edit > Special Object Properties > Message 

Result: The "PCS7 Message Configuration" dialog box is opened. 

Editing Message Types 

1. In SIMATIC Manager, select the FB whose message texts you want to edit, 

and open the PCS7 message configuration dialog box. 

2. Click on "More" to open the "Message text block". Fill out the text boxes for the 

message components "Origin," "OS area," and "Batch ID." 

3. Enter the message class and the event text for all events of the message 

blocks used and specify whether every event must be acknowledged 

individually. 

4. For the message parts that apply for all instances and should not be changed, 

select the "Locked" check box. 


1. Open SIMATIC Manager. Select the instance DB whose message texts you 

want to edit and open PCS7 message configuration function. 

2. Do not edit instance-specific message parts that are not locked. 


A5E00706944-01 16-25


16.3.3 Assigning and Editing Symbol-Related Messages 

16.3.3.1 How to Assign and Edit Symbol-Related Messages (CPU- 

Oriented) 

Symbol related messages (SCAN) are assigned directly to a signal in the symbol 

table. Permitted signals are all Boolean addresses: inputs (I), outputs (Q), and bit 

memory (M). You can assign these signals different attributes, messages texts, 

and up to 10 associated values with the message configuration function. You can 

make it easier to select signals in the symbol table by setting filters. 

With a symbol related message you can scan a signal in a predefined time interval 

to determine whether a signal change has taken place. 

Note 

The time interval is dependent on the CPU used. 


 

 

 

 

 

 

 

During processing, the signals for which you have configured messages are 

checked asynchronously to your program. The checks take place at the configured 

time intervals. The messages are displayed on the assigned display devices. 

Caution 

If you want to assign or edit symbol-related messages and, during the same work 

procedure, you have previously copied symbols between two symbol tables, you 

will then have to first close the symbol table that you no longer need to work in. 

Otherwise, you will not be able to save your message configurations. Under certain 

conditions, the last entries made in the message configuration dialog will be lost. 


16-26 A5E00706944-01


16.3.4 Assigning and Editing User-Specific Diagnostic Messages 

Using this function you can write a user entry in the diagnostic buffer and send a 

corresponding message which you create in the message configuration application. 

User-defined diagnostic messages are created by means of the system function 

SFC52 (WR_USMSG; Error Class A or B) which is used as a message block. You 

must insert the call for the SFC52 in your user program and allocate it the event ID. 

Requirements 

Before you can create a user-defined diagnostic message, you must have done the 

following: 

• Created a project in the SIMATIC Manager 

• Created a S7/M7 program in the project to which you want to assign one or 

more messages. 


To create and display a user-defined diagnostic message, proceed as follows: 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 16-27


16.4 Tips for Editing Messages 

16.4.1 Adding Associated Values to Messages 

To add current information (such as from a process) to block-related and symbolrelated 

messages, you can insert associated values at any point in a message text. 

To add values, proceed as follows: 

1. Create a block with the following structure: 

@@. 

2. Insert this block at the locations in the message text where the associated 

value is to be displayed. 

Element Type 

This parameter assigns a unique identification to the data type of the associated 

value: 

Element Type 

Y 

W 

X 

I 

D 

B 

C 

R 

Data Type 

BYTE 

WORD 

DWORD 

Integer 

Integer 

BOOL 

CHAR 

REAL 

The element type only uniquely specifies the data type transferred by the PLC. It is 

not used as a casting operator. 


16-28 A5E00706944-01


Format Code 

These codes specify the output format for the associated value on the display 

device. A format instruction is introduced by a "%" sign. For message texts, there 

are the following fixed message codes: 

Format Code 

%[i]X 

%[i]u 

%[i]d 

%[i]b 

%[i][.y]f 

%[i]s 

%t# 

Description 

Hex value with i index 

Unsigned decimal value 

with i index 

Signed decimal value 

with i index 

Binary value with i index 

Integer (fixed-point no.) 

Signed value with the format 

[ - ]dddd.dddd 

dddd: one or more digits with y places after the 

decimal point and i total places 

Character string (ANSI string) with i places 

Characters are printed to the first 0 byte (00hex). 

Access to text library. 

If the format code is too small, the value is still output in its full length. 

If the format code is too large, an appropriate number of blanks is output before the 

value. 

Note 

Note that you can also optionally specify the "[i]", in which case you must leave out 

the brackets when you enter this parameter. 


A5E00706944-01 16-29


Examples of Associated Values 

@1I%6d@: The value from associated value 1 is displayed as a decimal number 

having a maximum of 6 places. 

@2R%6f@: The value "5.4," for example, from associated value 2 is displayed as 

an integer "5.4" (three leading blanks). 

@2R%2f@: The value "5.4," for example, from associated value 2 is displayed as 

an integer "5.4" (for a number of places that is too small, truncation does not 

occur). 

@1W%t#Textbib1@: Associated value 1 of the data type WORD is the index with 

which the text to be used is referenced in the text library TextLib1. 

Note 

When using S7-PDIAG, you must always indicate "C" for the element type CHAR 

and "R" for the element type REAL. For all other element types valid for S7-PDIAG 

(BOOL, BYTE, WORD, INT, DWORD and DINT), you must always specify "X". 

If you wish to pass one of the ALARM_S blocks more than one associated value, 

you can send an array with a maximum length of 12 bytes. This can be, for 

example, a maximum of 12 bytes or characters, a maximum of 6 words or Int or a 

maximum of 3 double words, real or DInt. 

16.4.2 Integrating Texts from Text Libraries into Messages 

You can integrate as many texts as you want from a maximum of four different text 

libraries into one message. The texts can be placed freely, so their use in foreign 

language messages is also guaranteed. 


1. In the SIMATIC Manager, select the CPU or an object subordinate to the CPU 

and select the menu command Options > Text Libraries > System Text 

Libraries or Options > Text Libraries > User-Specific Text Libraries to 

open a text library. 

Caution 

You can only integrate texts from user text libraries into messages if you have 

selected to assign message numbers to the CPU (CPU-oriented message 

numbers). 

1. Determine the index of the text that you want to integrate. 

2. At the place in the message where you want the text to appear, enter a 

placeholder in the format @[Index]%t#[Textbib]@ 

Note 

[Index] = 1W, where 1W is the first associated value for the message of type 

WORD. 


16-30 A5E00706944-01


Example 

Configured message text: Pressure rose @2W%t#Textbib1@ 

Text library with the name Textbib1: 

Index German English 

1734 zu hoch too high 

The second associated value transferred has been assigned the value 1734. The 

following message is displayed: Pressure rose too high. 

16.4.3 Deleting Associated Values 

You can delete associated values by deleting the character string in the message 

text which represents the associated value. 


1. Locate the block of information in the message text corresponding to the 

associated value that you want to delete. 

The block begins with an @ sign, followed by a location designator identifying 

the associated value as well as a format code; it ends with another @ sign. 

2. Delete this information from the message text. 


A5E00706944-01 16-31


16.5 Translating and Editing Operator Related Texts 

Texts that are output on display devices during process editing were usually input 

in the same language used to program the automation solution. 

It may often be the case that an operator who is to react to messages on a display 

device does not speak this language. This user needs texts written in his native 

language to ensure smooth, problem-free processing and quick reaction to 

messages output by the system. 

STEP 7 allows you to translate any and all operator related texts into any language 

required. The only prerequisite for this is that you have already installed the 

language in your project (menu command: Options > Language for Display 

Devices in the SIMATIC Manager). The number of languages available is 

determined when Windows is installed (system property). 

In this way you can be certain that any user faced with such a message at a later 

date will have it displayed in the appropriate language. This system feature 

considerably increases processing security and accuracy. 

16.5.1 Translating and Editing User Texts 

You can create user texts for an entire project, for S7 programs, the block folder or 

individual blocks, and for the symbol table if messages are configured in these 

objects. They contain all texts and messages that can be shown on display 

devices, for example. For one project, there can be several lists of operator related 

texts that you can translate into the required languages. 

You can select the languages that are available in a project (menu command 

Options > Language for Display Devices…). You can also add or delete 

languages later. 

Exporting and Importing Operator Related Texts 

You can translate or edit operator related texts that were created in STEP 7 outside 

of STEP 7. To do this, export the displayed list of operator related texts in export 

files that you can edit with an ASCII-based Editor or a spreadsheet tool such as 

Microsoft EXCEL (Menu command Options > Manage Multilingual Texts > 

Export). After you have opened the file, the screen displays a table that contains a 

column for each language. The first column always displays the set standard 

language. After the texts have been translated, re-import them again in STEP 7. 

You can only import operator related texts into the part of the project from which 

you exported them. 


16-32 A5E00706944-01



Ensure that you have set your target languages for the text translation in SIMATIC 

manager, under menu command Options > Language for Display Devices. 

 

 

 

 

 

 

 

Note 

You can print user text only under the application used for the translation. 


A5E00706944-01 16-33


16.6 Translating and Editing Text Libraries 

16.6.1 User Text Libraries 

A user text library lets you view text or text segments dynamically, depending on 

the associated value. Here, the associated value provides the text library index for 

the current text. A placeholder is entered at the position were the dynamic text is to 

be displayed. 

You can create user libraries for a program in which you can enter text and select 

your own index. The application will automatically check the index in the user 

library for uniqueness. All messages available for this CPU can contain a crossreference 

to a user text library. 

The number of text libraries in a text library folder is unlimited. It is therefore 

possible, for example, to use the same program for different controlling tasks and 

merely adapt the text libraries to application requirements. 

Caution 

When you copy a message-type block that contains a cross-reference to a text 

library into another program, you must include the corresponding text libraries, or 

create a new text library of the same name or edit the cross-reference in the 

message text. 

An index is always assigned by default when you create a text entry. When you 

enter a new line, the application proposes the next free index as the default. 

Ambiguous indexes are not permitted in text library and are rejected by the 

application. 

16.6.2 Creating User Text Libraries 

To create a user text library, proceed as follows: 

1. In SIMATIC Manager, select the program or the subordinate object within the 

program for which you want to create a user text library. In SIMATIC Manager, 

select the menu command Insert > Text Library > Text Library Folder. 

Result: The "Text Library" folder is created. 

3. Now, select the "Text Library" folder. Select the menu command Insert > Text 

Library > User Text Library and name the text library. 

4. To open the new text library, select menu command Options > Text Libraries 

> User Text Library 

5. Now you can enter your text. 

Note 

An index is always assigned by default when you create a text entry. When you 

enter a new line, the application proposes the next free index as the default. 

Ambiguous indexes are not permitted in text library and are rejected by the 

application. 


16-34 A5E00706944-01


16.6.3 How to Edit User Text Libraries 

To edit existing user text libraries, proceed as follows: 

1. In SIMATIC Manager, select the program or the subordinate object within the 

program whose text library you want to edit and then select the menu 

command Options > Text Libraries > User Text Library. 

2. Select the text library you want to open from the "Available Text Libraries" 

dialog box. 

3. Edit the displayed texts. There are various editing functions available (such as 

Find and Replace). 

You can enter your own texts. You can always change the index that is 

automatically generated for the texts. If you should happen enter a previously 

assigned index, its value is highlighted in red. 

To insert a new row, select the menu command Insert > New Row or click on 

the corresponding toolbar icon. 

4. If you require a hardcopy, print the texts. 

5. Close the user text library after you have completed all tasks. 

6. Close the application after you have edited all texts required. 

Caution 

When you copy a message-type block that contains a cross-reference to a text 

library into another program, you must include the corresponding text libraries, or 

create a new text library of the same name or edit the cross-reference in the 

message text. 

When you change the name of an existing text library, you will render the 

associated values cross-referenced to this text library invalid in already configured 

messages! 


A5E00706944-01 16-35


16.6.4 System Text Libraries 

System text libraries are automatically created when blocks are generated, e.g. in 

"Report System Errors". The user can not create system text libraries and can only 

edit existing text libraries. 

All messages available for this CPU can contain a cross-reference to a text library. 

16.6.5 Translating Text Libraries 

System text libraries and user text libraries provide a list of texts that can be 

integrated into messages, updated dynamically at run time, and shown on a 

programming device or other display device. 

The texts in system text libraries are provided by STEP 7 or STEP 7 optional 

packages. There can be several text libraries assigned to one CPU. You can 

translate these texts into the required languages. 

In the SIMATIC Manager, you can select the languages that are available in a 

project (menu command Options > Language for Display Devices…). You can 

also add or delete languages later. 

When you initiate the translation of a text library (Menu command Options > 

Manage Multilingual Texts > Export), an export file will be generated that you 

can edit under Microsoft EXCEL, for example. After you have opened the file, the 

screen displays a table that contains a column for each language 

Caution 

Never open a *.cvs export file with double-click on the file. Always use menu 

command File > Open under Microsoft EXCEL to open the file. 

Note 

You can print user text only in the application used for the translation. 

Example of an export file 

German 

ausgefallen 

gestört 

Parametrierfehler 

English 

Failure 

Disruption 

Faulty parameter 

assignment 


16-36 A5E00706944-01



In the SIMATIC Manager, with the menu command Options > Language for 

Display Devices…, make sure that you have set the languages into which you 

want to translate a text library. 

 

 

 

 

 

 

 

 

 


A5E00706944-01 16-37


16.7 Transferring Message Configuration Data to the 

Programmable Controller 

Overview 

Use the transfer program AS-OS Engineering to transfer the message 

configuration data generated to the WinCC database. 

Requirements 

Before you start the transfer, the following requirements must be fulfilled: 

• You have installed "AS-OS Engineering" 

• You have generated the configuration data for creating messages. 


 

 

 

 

 


16-38 A5E00706944-01


16.8 Displaying CPU Messages and User-Defined 


With the "CPU Messages" function (Menu command PLC > CPU Messages), you 

can display asynchronous messages on diagnostic events and user-defined 

diagnostic messages as well as messages from ALARM_S blocks (SFC 18 and 

SFC 108 for generating block-related messages that are always acknowledged as 

well as SFC 17 and SFC 107 for generating block-related messages that can be 

acknowledged). 

You can also start the message configuration application from the CPU Messages 

application using the menu command Edit > Message > User-Defined 

Diagnostics and create user-defined diagnostic messages. The requirement for 

this is that you started the CPU Messages application via an online project. 

Display Options 

With the "CPU Messages" function, you can decide whether and how online 

messages for selected CPUs are displayed. 

• "Highlight in the Task Bar": As soon as a message is received and the window 

is not on top, "CPU Message" is highlighted in the Windows task bar. 

• "Leave in the Background": The CPU messages are received in the 

background. The window remains in the background when new messages are 

received and can be brought to the foreground if required. 

• "Ignore Message": New CPU messages are not displayed and, in contrast to 

the other two modes, not archived. 

In the "CPU Messages" window you can select the "Archive" tab or the "Interrupt" 

tab. In both tabs you can select the menu command View > Display Info Text to 

specify whether the messages are displayed with or without Info text. The user can 

sort the columns as required. 


A5E00706944-01 16-39


"Archive" Tab 

Incoming messages are here displayed and archived, sorted by the event message 

time. The volume of the archive (between 40 and 3000 CPU messages) can be set 

via menu command Options > Settings in the "Settings - CPU Messages" dialog 

box. The oldest queued message will be deleted if the set archive volume is 

exceeded. 

Acknowledgeable messages (ALARM_SQ and ALARM_DQ) are displayed in bold 

letters. You can acknowledge these messages under the menu command Edit > 

Acknowledge CPU Message. 


16-40 A5E00706944-01


"Interrupt" Tab 

The status of queued messages from ALARM_S blocks that have not yet been 

received or acknowledged is also displayed in the "Interrupt" tab. 

You can select the menu command View > Multiline Messages to display 

messages on one or more lines. In addition, you can sort the columns as 

necessary. 

Updating Messages from ALARM_S Blocks 

During updating all unsent or unacknowledged messages are entered in the 

archive again. The messages are updated: 

• If a restart is performed on the module to which the messages relate (not a cold 

restart) 

• If you click the option "A" for messages from ALARM_S Blocks in the module 

list. 


To configure CPU messages for selected modules: 

 

 

 

 

 


A5E00706944-01 16-41


16.8.1 Configuring CPU Messages 

To configure CPU messages for selected modules, proceed as follows: 

1. In the SIMATIC Manager, start the CPU Messages application via an online 

project. To do this, select an S7 program online and call the CPU Messages 

application for the selected CPU using the menu command PLC > CPU 

Messages. 

Result: The "CPU Messages" application window appears which lists the 

registered CPU. 

2. You can extend the list of registered CPUs by repeating step 1. for other 

programs or interfaces. 

3. Click the check box in front of the list entries and specify which messages 

should be received for the module: 

A: activates messages from ALARM_S blocks (SFC 18 and SFC 108 for 

generating block-related messages that are always acknowledged as well as 

SFC 17 and SFC 107 for generating block-related messages that can be 

acknowledged), for example, reporting process diagnostic messages from S7 

PDIAG, S7-GRAPH, or system errors. 

W: activates diagnostic events. 

4. Set the size of the archive. 

Result: As soon as the above messages occur, they are written in the 

message archive and displayed in the form you selected. 

Note 

The CPUs for which you have called the menu command PLC > CPU Messages 

in the SIMATIC Manager are entered in the list of registered modules in the "CPU 

Messages" application window. The entries in the list are retained until they are 

deleted in the "CPU Messages" application window. 

16.8.2 Displaying Stored CPU Messages 

CPU messages are always recorded in the archive unless you have selected the 

menu command View > Ignore Message. All archived messages are always 

displayed. 


16-42 A5E00706944-01


16.9 Configuring the 'Reporting of System Errors' 

Introduction 

When a system error occurs, S7 components and DP standard slaves (slaves 

whose properties are determined by their GSD file) can trigger organization block 

calls. 

Example: If there is a wire break, a module with diagnostic capability can trigger a 

diagnostic interrupt (OB82). 

For the system errors that occur, the S7 components provide information. The start 

event information, that is, the local data of the assigned OB (which contain the data 

record 0, among other things), provide general information on the location (such as 

the logical address of the module) and type (such as channel error or backup 

failure) of the error. 

In addition, the error can be specified in greater detail by means of additional 

diagnostic information (reading data record 1 with SFC51 or reading the diagnostic 

message of DP standard slaves with SFC13). Examples of this would be channel 0 

or 1 and wire break or measuring-range overrun. 

With the Report System Error function, STEP 7 offers a convenient way to display 

diagnostic information supplied by the component in message form.. 

The necessary blocks and message texts are automatically generated by STEP 7. 

All the user has to do is load the generated blocks into the CPU and transfer the 

texts to connected HMI devices. 

You will find a complete overview of the supported diagnostic information for 

various slaves in the section Supported Components and Functional Scope 


A5E00706944-01 16-43



 

 

 

 

 

 

 

 

 

 

The messages are sent by means of the standard message path ALARM_S/SQ to 

CPU Messages on the programming device or to the connected HMI devices. 


16-44 A5E00706944-01


16.9.1 Supported Components and Functional Scope 

Diagnostic Block 

The components of S7 300 stations, S7 400 stations, DP slaves, and WinAC are 

supported by Report System Error, as long as they support functions such as 

diagnostic interrupt insert/remove module interrupt, and channel-specific 

diagnostics. 

The following components are not supported by Report System Error: 

• M7, C7, and PROFIBUS-DP configurations on DP master interface module (CP 

342-5 DP) in S7-300 stations 

In the case of a restart, you must also note that missing interrupt messages can 

occur. This is because the message acknowledgement memory of the CPU cannot 

be deleted during restart but Report System Error resets the internal data. 

In the two tables that follow, you will find all the diagnostic blocks of the various 

PROFIBUS slaves supported by "Report System Error" 

ID 

(faulty slot) 

Channel 

Designation 

(channel error) 1) 

Module Status 

(module error, 

incorrect/no module) 

Header ID 2) 0x01 0x10 0x00 

Type 0x82 

ET 200S 

Message: 

"Diagnostics is 

available" 

Plain-Text 

Message 

Plain-Text Message - 

Device 

Designation 

0x00 + 1 Byte 

Diagnostic Info 

ET 200M Not Evaluated Not Evaluated Not Evaluated - 

ET 200X 

Message: - - - 


available" 

ET 200X DESINA Message: Plain-Text Plain-Text Message - 


available" 

Message 

ET 200L not evaluated - - 

ET 200B Digital 

Message: "Module 

Malfunction" 

ET 200B Analog - - 

ET 200C Digital 

ET 200 C Analog 

ET 200 U 

ET 200 iS 

Message: 

"Diagnostics 

Available" 

Message: 

"Diagnostics 

Available" 

Message: 

"Diagnostics 

Available" 

Plain-text 

message 

Plain-text message 


Malfunction" 


Malfunction" 

ET 200 eco - - - Plain-text 

message 

DP AS-i Link Message: 

"Diagnostic data 

available" 

- Plain-text message - 


A5E00706944-01 16-45


Diagnostics Block DS0/DS1 1 Other Instancing 

Header ID 2 

0x00 

Type 0x01 

0x00 

Other Type 

ET 200S 

ET 200M Plain-text message Not Evaluated 

ET 200X 

ET 200X DESINA 


ET 200L 


ET 200B Digital 

ET 200B Analog 


ET 200 C Digital 

ET 200 C Analog 


ET 200 iS 


ET 200 eco - - 

DP AS-i Link 

Message: "Module error" 

In the tables that follow, you will find all the diagnostic blocks of the various 

PROFIBUS slaves supported by "Report System Error". 

Diagnostics 

Block 

ID 

(faulty slot) 

Channel 

Designation 

(channel error) 

1) 

Module Status 

(module error, 

incorrect/no 

module) 

Header ID 2) 0x01 0x10 0x00 

Type 0x82 

ET 200 S 

SCALANCE 

Switches 

Message: 

"Diagnostics are 

available" 

Plain-text 

Message 

Plain-text 

Message 

- - Plain-text 

Message 

Device Designation 

0x00 + 1 Byte 

Diagnostic Info 

- 

- 

Diagnostics Block DS0/DS1 1) Other Instancing 

Header ID 2 

0x00 

Type 0x01 

0x00 

Other Type 

ET 200 S - - 

SCALANCE switches Plain-text message Not evaluated 

1) DS0: Standard diagnostics, for example module fault, external auxiliary voltage or front connector missing, 

extent 4 bytes, contained in the local data of the OB 82. 

DS1: Channel error, defined differently for each channel type, readable in the user program via SFC 51. 

The texts come from the S7 HW diagnostics. 

2) Header identifier: Identifier in the diagnostic message which identifies different diagnostic parts. 


16-46 A5E00706944-01


The diagnostic message (also called Norm slave message) is made up of the 

diagnostic blocks mentioned above and can be read in the user program via 

SFC 13. 

In STEP 7 the diagnostics message is displayed via the call of the module state in 

the on-line window "HW Config" (diagnose hardware) in the "DP Slave 

Diagnostics" tab card under "Hex display". 

Diagnostic Repeater: The messages of the Diagnostic Repeater are output as 

plain-text. The text is read from the GSD file. 

PROFINET 

• With PROFINET IO, the channel diagnostics are output as a plain-text 

message. 

• ET 200S: Slaves with packed addresses are supported. 

• With PROFINET IO devices, manufacturer-specific diagnostics are supported. 


A5E00706944-01 16-47


16.9.2 Settings for "Report System Error" 

You have several possibilities for calling the dialog for the settings: 

• In HW Config, select the CPU for which you would like to configure the reporting 

of system errors. Then select the menu command Options > Report System 

Error. 

• If you have already generated blocks for reporting system errors, you can call 

up the dialog by double-clicking a generated block (FB, DB). 

• In the Properties dialog of the station, select the option for automatic call up 

during Save and Compile the configuration. 

You get to the option for automatic call up during Save and Compile as follows: 

1. In the SIMATIC Manager, select the appropriate station. 

2. Select the menu command Edit > Object Properties. 

3. Select the Settings tab. 

Note 

You can also open the "Settings" tab of the properties dialog in HW Config via 

menu command Station > Properties. 

In the dialog box, enter the following, in addition to other things: 

• Which FB and which assigned instance DB should be generated 

• Whether reference data should be generated 

• Whether warnings should always be displayed during the generation of Report 

System Error. 

• Whether the dialog box should appear when Report System Error is 

automatically called after saving and compiling the configuration (see setting 

above) 

• Generating error OBs: whether or not error OBs that are not yet available 

should be generated in the S7 program and in which OBs "Report System 

Error" is to be called. 

• The CPU behavior on error: You can determine which error class event is 

trigger the CPU to STOP mode. 

• The appearance of the messages (structure and order of the possible text parts) 

• Whether messages should be acknowledgeable 

• Which parameters the user block interface should contain 

You can find more detailed information in the Help on the called dialog. 


16-48 A5E00706944-01


16.9.3 Generating Blocks for Reporting System Errors 

After you have completed your settings for reporting system errors, you can 

generate the required blocks (FBs and DBs, including DBs that do not yet exist, 

depending on the configuration). To do this, click on the "Generate" button in the 

"Report System Errors" dialog box. 

The following blocks are generated: 

• Diagnostic FB (default: FB49) 

• Instance DB for the diagnostic FB (default: DB49) 

• Error OBs (if you have selected this option in the "OB Configuration" dialog 

box), 

• Optional user block called by the diagnostic FB 

16.9.4 Generated FB, DB 

The generated FB evaluates the local data of the error OB, reads any additional 

diagnostic information of the S7 component that triggered the failure, and 

generates the appropriate message automatically. 

The FB has the following properties: 

• Language of generation RSE (Report System Error) (also applies to the 

generated instance DB) 

• Know-how protected (also applies to the generated instance DB) 

• Delays arriving interrupts during run time 

• Calls up the dialog for setting the "Report System Error" function by means of 

double-click (also applies to the generated instance DB). 


A5E00706944-01 16-49


User Block 

Because the diagnostics FB is know-how protected, you cannot edit it. However, 

the FB provides an interface for the user program so that you can access such 

things as the error status or the message number. 

The block for evaluating in the user program (can be set in the User Block tab of 

the of the dialog) is called in the generated FB with the selected parameters. The 

following parameters are available: 

Name Data Type Comments 

EV_C BOOL //Message incoming (TRUE) or outgoing (FALSE) 

EV_ID DWORD //Generated message number 

IO_Flag BYTE //Input module: B#16#54 Output module: B#16#55 

logAdr WORD //Logical address 

TextlistId WORD //ID of the text library (default text library = 1) 

ErrorNo WORD //Generated error number 

Channel_Error BOOL //Channel error (TRUE) 

ChannelNo WORD //Channel number 

ErrClass WORD //Error Class 

HErrClass WORD //Error Class of H Systems 

If the user FB does not exist yet, it is created by the SFM with the selected 

parameters. 

The error texts generated for standard errors are arranged as follows: 

Error Number 

(decimal) 

Error-OB Affected 

Error Code in the OB 

from to from to 

1 86 OB 72 B#16#1 B#16#56 

162 163 OB 70 B#16#A2 B#16#A3 

193 194 OB 72 B#16#C1 B#16#C2 

224 OB 73 B#16#E0 

289 307 OB 81 B#16#21 B#16#33 

513 540 OB 82 

865 900 OB 83 B#16#61 B#16#84 

1729 1763 OB 86 B#16#C1 B#16#C8 


16-50 A5E00706944-01


Error numbers greater than 12288 refer to channel errors. If you view the error 

number in hexadecimal representation, you can calculate the channel type and 

recognize the error bit. For an exact description, refer to the respective module 

help or channel help text. 

Example: 

12288 = W#16#3000 -> high byte 0x30 - 0x10 = channel type 0x20 (CP interface); 

low byte 0x00, means error bit 0 

32774 = W#16#8006 -> high byte 0x80 - 0x10 = channel type 0x70 (digital input); 

low byte 0x06, means error bit 6 

16.9.5 Creating Foreign-Language Message Texts in 'Report System 

Error' 

You can display the messages configured in "Report System Error" in the 

languages that you installed when you installed STEP 7. 

To do so, proceed as follows: 

1. In the SIMATIC Manager, select the Options > Display Language... menu 

command. In the dialog box that is then displayed, add the desired language to 

your project. 

2. Confirm your settings with "OK". 

3. In HW Config, select the Options > Report System Error... menu command. 

In the dialog box that is then displayed, click the "Generate" button. 

Result: The message texts are generated for all the languages that you 

installed, but they are only displayed in the language that you have set as the 

default in the "Add/Delete Language, Set Default Language" dialog box by 

clicking the "Set as Default" button. 

Example 

You have installed STEP 7 in German, English and French, and these languages 

are defined in your project. Now you generate the message texts as described 

above. To display the messages texts in a given language, set this language as the 

default in the "Add/Delete Language, Set Default Language" dialog box. 


A5E00706944-01 16-51



16-52 A5E00706944-01

17 Controlling and Monitoring Variables 

17.1 Configuring Variables for Operator Control and 

Monitoring 

Overview 

STEP 7 provides a user-friendly method of controlling and monitoring variables in 

your process or programmable controller using WinCC. 

The advantage of this method over previous methods is that you no longer need to 

configure data separately for each operator station (OS), you simply configure once 

using STEP 7. You can transfer the data generated when you configure with 

STEP 7 to the WinCC database using the transfer program AS-OS Engineering 

(part of the software package "Process Control System PCS7"), during which the 

consistency of the data and their compatibility with the display system are checked. 

WinCC uses the data in variable blocks and graphic objects. 

Using STEP 7, you can configure or modify operator control and monitoring 

attributes for the following variables: 

• Input, output, and in/out parameters in function blocks 

• Bit memory and I/O signals 

• Parameters for CFC blocks in CFC charts 


The procedure for configuring operator control and monitoring variables is 

dependent on the selecting programming/configuration language and the type of 

variables you want to control and monitor. The basic procedure always includes the 

following steps, however: 

1. Assign system attributes for operator control and monitoring to the parameters 

of a function block or to the symbols in a symbol table. 

The step is not required in CFC because you take blocks that have already 

been prepared from a library. 

2. Assign the variables you want to control and monitor with the required 

attributes and logging properties in a dialog box (S7_m_c). In the Operator 

Interface dialog box (menu command Edit > Special Object Properties > 

Operator Interface), you can change WinCC attributes, such as limit values, 

substitute values, and protocol properties, etc. 

3. Transfer the configuration data generated with STEP 7 to your display system 

(WinCC) by means of the AS-OS Engineering tool. 


A5E00706944-01 17-1

Controlling and Monitoring Variables 

Naming Conventions 

For the configuration data for WinCC to be saved and transferred, they are stored 

under a unique name automatically assigned by STEP 7. The names of the 

variables for operator control and monitoring, the CFC charts, and the S7 programs 

form part of this name and for this reason are subject to certain conventions: 

• The names of the S7 programs in an S7 project must be unique (different 

stations may not contain S7 programs with the same name). 

• The names of the variables, S7 programs, and CFC charts may not contain 

underscores, blanks, or the following special characters: [ ‘ ] [ . ] [ % ] [ - ] [ / ] 

[ * ] [ + ]. 


17-2 A5E00706944-01


17.2 Configuring Operator Control and Monitoring 

Attributes with Statement List, Ladder Logic, and 

Function Block Diagram 

Overview 

Using the procedure described below, you can make function block parameters 

suitable for operator control and monitoring and assign the required O, C, and M 

attributes to associated instance DBs or shared DBs in your user program. 

Requirements 

You must have created a STEP 7 project, an S7 program, and a function block. 


 

 

 

 

 


A5E00706944-01 17-3


17.3 Configuring Operator Control and Monitoring 

Attributes via the Symbol Table 

Overview 

Independent of the programming language used, you can configure the following 

variables using the procedure described below: 

• Bit memory 

• I/O signals 

Requirement 

Before you start, the following requirements must be fulfilled: 

• You have created a project in the SIMATIC Manager. 

• An S7 program with a symbol table must exist in this project. 

• The symbol table must be open. 


 

 

 


17-4 A5E00706944-01


17.4 Changing Operator Control and Monitoring Attributes 

with CFC 

Overview 

With CFC, you create your user program by selecting blocks that already have 

operator control and monitoring capabilities from a library, and placing and linking 

them in a chart. 

Requirement 

You have inserted an S7 program in a STEP 7 project, created a CFC chart, and 

placed blocks in it. 


 

Note 

If you use blocks which you have created yourself and to which you have assigned 

the system attribute S7_m_c, you can give these blocks operator control and 

monitoring capabilities by activating the "Operator Control and Monitoring" check 

box in the "Operator Control and Monitoring" dialog box (menu command Edit > 

Special Object Properties > Operator Control and Monitoring). 


A5E00706944-01 17-5


17.5 Transferring Configuration Data to the Operator 

Interface Programmable Controller 

Introduction 

Using the transfer program AS-OS Engineering you transfer the configuration data 

for operator control and monitoring generated to the WinCC database. 

Requirement 

Before you start the transfer, the following requirements must be fulfilled: 

• You have installed the program AS-OS Engineering. 

• You have generated the configuration data for operator control and monitoring. 


To transfer the configuration data for operator control and monitoring to the WinCC 

database, proceed as follows: 

 

 

 

 

 


17-6 A5E00706944-01

18 Establishing an Online Connection and 

Making CPU Settings 

18.1 Establishing Online Connections 

An online connection between programming device and programmable logic 

controller is needed to download S7 user programs/blocks, upload blocks from the 

S7 programmable controller to the programming device, and for other activities: 

• Debugging user programs 

• Displaying and changing the operating mode of the CPU 

• Displaying and setting the time and date of the CPU 

• Displaying module information 

• Comparing blocks online and offline 

• Diagnosing hardware 

To establish an online connection, the programming device and programmable 

logic controller must be connected via a suitable interface (for example, multipoint 

interface (MPI)). You can then access the programmable controller via the online 

window of the project or the "Accessible Nodes" window. 


A5E00706944-01 18-1

Establishing an Online Connection and Making CPU Settings 

18.1.1 Establishing an Online Connection via the "Accessible Nodes" 

Window 

This type of access enables you to access a programmable logic controller quickly, 

for test purposes, for example. You can access all the accessible programmable 

modules in the network. Select this method if no project data about the 

programmable controllers are available on your programming device. 

You open the "Accessible Nodes" window using the menu command PLC > 

Display Accessible Nodes. In the "Accessible Nodes" object, all the nodes 

accessible in the network are displayed with their address. 

Nodes that cannot be programmed with STEP 7 (such as programming devices or 

operator panels) can also be displayed. 

The following additional information can also be shown in parentheses: 

• (direct): This node is directly connected to the programming device 

(programming device or PC). 

• (passive): Programming and status/modify via PROFIBUS DP is not possible 

with this node 

• (waiting): This node cannot be communicated with because its configuration 

does not match the rest of the settings in the network. 

Finding directly connected nodes 

The additional information "direct" is not supported for PROFINET nodes. To still 

be able to find directly connected nodes, select the PLC > Diagnostics/Settings > 

Node Flashing Test menu command. 

In the dialog box that is displayed, you can set the flashing duration and then start 

the flashing test. The directly connected node will be identified by a flashing 

FORCE LED. 

The flashing test cannot be carried out if the FORCE function is active. 


18-2 A5E00706944-01


18.1.2 Establishing an Online Connection via the Online Window of the 

Project 

Select this method if you have configured the programmable controller in a project 

on your programming device/PC. You can open the online window in the SIMATIC 

Manager using the menu command View > Online. It displays the project data on 

the programmable controller (in contrast to the offline window that displays the 

project data on the programming device/PC). The online window shows the data on 

the programmable controller both for the S7 program and for the M7 program. 

You use this view of the project for functions involving access to the programmable 

controller. Certain functions in the "PLC" menu of the SIMATIC Manager can be 

activated in the online window but not in the offline window. 

There are two types of access as follows: 

• Access with Configured Hardware 

This means you can only access modules which were configured offline. Which 

online modules you can access is determined by the MPI address set when the 

programmable module was configured. 

• Access without Configured Hardware 

The requirement for this is an existing S7 program or M7 program which was 

created independently of the hardware (meaning it lies directly beneath the 

project). Which online modules you can access is determined here by 

specifying the corresponding MPI address in the object properties of the S7/M7 

program. 

Access via the online window combines the data on the programmable control 

system with the relevant data on the programming device. If, for example, you 

open an S7 block beneath a project online, the display is made up as follows: 

• Code section of the block from the CPU in the S7 programmable logic 

controller, and 

• Comments and symbols from the database in the programming device 

(provided they exist offline) When you open blocks directly in the connected 

CPU without an existing project structure, they are displayed as they are found 

in the CPU, which means without symbols and comments. 


A5E00706944-01 18-3


18.1.3 Online Access to PLCs in a Multiproject 

Cross-project access with an assigned PG/PC 

The "Assign PG/PC" function for the objects "PG/PC" and "SIMATIC PC Station" 

are also available for the multiproject. 

You can specify the target module for online access in any project of the 

multiproject. This procedure is the same as if you were working with one project 

only. 

Requirements 

• PGs/PCs or PC stations you want to use for online access to PLCs must have 

been assigned in any one project of the multiproject. 

Note: The assigned PG/PC or PC station is highlighted in yellow color when the 

corresponding project is open. 

The PG/PC assignment is only visible if the PG that opens the project is 

properly assigned. 

• The cross-project subnets are merged. 

• All projects of the multiproject have been compiled and configuration data have 

been downloaded to the participating stations; for example, to provide routing 

information to all participating modules for establishing connections between the 

PG/PC and the target module. 

• The target modules can be accessed across the networks. 


18-4 A5E00706944-01


Possible problems when working with distributed projects 

The PG/PC assignment is not visible if the allocation of projects is changed and a 

project is opened on a PG/PC on which it was not created. 

Nonetheless, the configured PG/PC object still maintains the "assigned" status - 

but with the "wrong" PG/PC. 

In this case you must clear the existing assignment and then reassign the PG/PC 

object. Online access to modules available within the multiproject is then possible 

without any problem. 

Tip for working with distributed projects 

If more than one of the team members want to access the PLCs online on their PG, 

it would be useful to create one "PG/PC" or "SIMATIC PC station" object in the 

multiproject and then set up an assignment for each one of the PGs. 

Depending on which PG has opened the project, SIMATIC Manager indicates only 

the object assigned to this PG with a yellow arrow. 


A5E00706944-01 18-5


18.1.4 Password Protection for Access to Programmable Controllers 

Using password protection you can: 

• Protect the user program in the CPU and its data from unauthorized changes 

(write protection) 

• Protect the programming know-how in your user program (read protection) 

• Prevent online functions that would interfere with the process 

You can only protect a module or the content of a MMC (e.g. for a CPU 31xC) with 

a password if the module supports this function. 

If you want to protect a module or the content of a MMC with a password, you must 

define the protection level and set the password in the course of assigning the 

module parameters and then download the changed parameters to the module. 

If you need to enter a password to execute an online function or access the content 

of a MMC, the "Enter Password" dialog box is displayed. If you enter the correct 

password, you are given access rights to modules for which a particular protection 

level was set during parameter assignment. You can then establish online 

connections to the protected module and execute the online functions belonging to 

that protection level. 

Using the menu command PLC > Access Rights > Setup, you can call the "Enter 

Password" dialog box directly. By doing this, for example at the beginning of a 

session, you can enter the password once and will no longer be queried during 

later online accesses. The password remains effective until either the SIMATIC 

Manager is closed or the password is cancelled with the menu command PLC > 

Access Rights > Cancel. 

CPU Parameter 

Test 

operation/process 

operation 

(not for S7-400 or 

CPU 318-2) 

Protection level 

Remarks 

Can be set in the "Protection" tab. 

In process operation, test functions such as program status or 

monitor/modify variables are restricted so that the set permissible 

scan cycle time increase is not exceeded. This means, for example, 

that no call conditions are allowed in program status and the status 

display of a programmed loop is interrupted at the point of return. 

Testing using breakpoints and single-step program execution cannot 

be used in process operation. 

In test operation, all test functions via programming device/PC even if 

they cause considerable increases to the scan cycle time can be 

used without restrictions. 

Can be set in the "Protection" tab. You can make write or read/write 

access to the CPU dependent on knowing the correct password. The 

password is set in this tab. 


18-6 A5E00706944-01


18.1.5 Updating the Window Contents 

You should note the following: 

• Changes in the online window of a project as a result of user actions (for 

example, downloading or deleting blocks) are not automatically updated in any 

open "Accessible Nodes" windows. 

• Any such changes in the "Accessible Nodes" window are not automatically 

changed in any open online windows of a project. 

To update the display in a parallel open window, you must refresh the display in 

this window explicitly (using the menu command or the function key F5). 


A5E00706944-01 18-7


18.2 Displaying and Changing the Operating Mode 

18.2.1 Displaying and Changing the Operating Mode 

With this function you can, for example, switch the CPU to RUN again after 

correcting an error. 

Displaying the Operating Mode 

1. Open your project and select an S7/M7 program, or open the "Accessible 

Nodes" window using the menu command PLC > Display Accessible Nodes 

and select a node ("MPI=..."). 

2. Select the menu command PLC > Diagnostics/Settings > Operating Mode. 

This dialog box displays the current and the last operating mode and the current 

setting of the mode selector on the module. For modules for which the current 

keyswitch setting cannot be displayed, the text "Undefined" is displayed. 

Changing the Operating Mode 

You can change the mode of the CPU using the buttons. Only those buttons are 

active that can be selected in the current operating mode. 


18-8 A5E00706944-01


18.3 Displaying and Setting the Time and Date 

18.3.1 CPU Clocks with Time Zone Setting and Summer/Winter Time 

In addition to the time-of-day/date you can also configure or evaluate the following 

settings in new CPUs (Firmware V3 or higher), using STEP 7 V5.1, Service Pack 2: 

• Summer/Winter Time 

• Offset factors for displaying time zones 

Display of Time Zones 

The system operates with a TOD that is global, continuous and free of interrupts, 

namely the Module Time. 

The local automation system allows the calculation of a Local Time that differs from 

Module Time and which can be used by the user program. Local Time is not 

entered directly, but are rather calculated using the Module Time plus/minus a time 

difference to Module Time). 

Summer/Winter Time 

You can also set Summer or Winter Time when you set up the TOD and the date. 

When switching from summer time to winter time, for example, per user program 

only the time difference to the Module Time is taken into account. You can effect 

this change-over with a block made available to you via the Internet. 

Reading and Adjusting the TOD and The TOD Status 

The summer/winter time identifier and time difference to the Module Time are 

included in the Time-Of-Day (TOD) status. 

You have the following options to read or adjust the TOD and its status: 

With STEP 7 (online) 

• Via menu command PLC > Diagnostics/Setting > Adjust TOD (read and 

adjust) 

• Via the "Module Information" dialog box, "Time System" tab (read only) 

In the user program 

• SFC 100 "SET_CLKS" (read and adjust) 

• SFC 51 "RDSYSST" with SZL 132, Index 8 (read only) 

Time Stamp in the Diagnostic Buffer, Messages and OB-Start Information 

Time stamps are generated using the Module Time. 


A5E00706944-01 18-9


TOD Interrupts 

OB 80 is called if TOD interrupts were not triggered due to the "Time jump" when 

winter time is switched to summer time. 

For summer/winter time conversion the periodicity is maintained for TOD interrupts 

with minute and hourly periodicity. 

TOD Synchronization 

A CPU that is configured as TOD Master (for example, in the CPU register 

"Diagnostics/Clock"), always synchronizes other clocks with the Module Time and 

the current TOD status. 

18.4 Updating the Firmware 

18.4.1 Updating Firmware in Modules and Submodules Online 

As of STEP 7 V5.1 Service Pack 3, you can update modules or submodules on a 

station in a standardized way online. To do so, proceed as described below: 

Concept 

To update the firmware on a module such as a CPU, a CP or an IM, you must 

obtain the files (*.UPD) containing the latest firmware. 

Select one of these files and download it to the module (PLC Menu). 


18-10 A5E00706944-01


Prerequisites 

The module in the station whose firmware is to be updated must be online, such 

when the programming device (PG) is connected to the same MPI PROFIBUS or 

Ethernet as the module whose firmware is to be updated. The firmware can also be 

updated when the programming device (PG) is connected to the MPI interface of 

the DP master CPU and the module whose firmware is to be updated is connected 

at the PROFIBUS of the DP interface or the Ethernet of the PN interface. The CPU 

must support S7 routing between the MPI interface and the DP interface or 

between the MPI interface and the PN interface. 

The module itself must support Firmware updates. 

The files containing the latest firmware versions must be available in the file system 

on your PG/PC. Only files for one firmware version must be in one folder. 

(1) PROFIBUS or Ethernet subnet 

(2) MPI subnet 

(3) CPU with MPI interface and DP interface or PN interface (with S7 routing) 


A5E00706944-01 18-11


Procedure in HW Config 

1. Open the station containing the module to be updated. 

2. Select the module 

For PROFIBUS DP interface modules such as an IM 151, select the icon for 

the DP slave. In this case, it is the one that stands for ET 200S. 

3. Select the menu command PLC > Update Firmware. 

You can only activate the menu command if the selected module or the 

selected DP slave supports the "Update firmware" function. 

4. In the "Update firmware" dialog that is displayed, click the "Browse" button and 

select the path to the firmware update files (*.UPD). 

5. After you have selected a file, the lower fields of the "Update firmware" dialog 

will contain information telling you for which modules the file is suitable and as 

of which firmware version. 

6. Click the "Run" button. 

STEP 7 checks whether the selected file can be interpreted by the module. If 

the check result is positive, the file is downloaded to the module. 

If the operating mode of the CPU needs to be changed, dialogs will prompt you 

to carry out these steps. 

The module then carries out the firmware update independently. 

Note: For a firmware update, such as to a CPU 317-2 PN/DP, a separate 

connection is usually established to the CPU. In such case, the process can be 

interrupted. If no resources are available for another connection, the existing 

connection is automatically used instead. In this case, the connection cannot 

be interrupted. The "Cancel" button in the transfer dialog is grayed out and 

unavailable. 

7. In STEP 7, check (read out the CPU diagnostic buffer) whether the module 

was able to start up with the new firmware. 

Procedure in SIMATIC Manager 

The function can be activated when the window "Accessible Nodes" is open. The 

procedure corresponds to that in HW Config. The menu command also is PLC > 

Firmware update. STEP 7 however only checks if the module supports the function 

at the time of the execution. 

Firmware Update for Modules in Redundant Mode 

As of STEP 7 V5.4, a firmware updates for a modules during redundant mode is 

supported, such as for the IM 153-2BA00 with an active backplane bus at an H 

station. You can carry out a firmware update for the redundant IMs in one process; 

the redundant IM will automatically be provided with the latest firmware version. 

Requirement: The programming device (PG) must be connected to the same 

PROFIBUS as one of the IMs and you perform the update by means of "Accessible 

Nodes" in the SIMATIC Manager. 


18-12 A5E00706944-01


Principle 

Consequences of updating the firmware during operation 

You can decide to activate the new firmware immediately after updating via an 

option in the update dialog. 

If you select this option, the station performs a restart like after POWER 

OFF/POWER ON. As result, it may happen that a CPU remains in STOP mode or 

the processing of the user program is adversely affected. You will need to take 

appropriate precautions in the operation of your plant to anticipate and 

accommodate these conditions. 

For example, during a restart all modules of the station will fail, including the 

existing F I/O. 

The F I/O outputs a communication error to the interface during POWER OFF and 

switches off safely - it is passivated. This passivation is not cleared by restarting 

the interface. You must depassivate the modules individually. However, the safetyrelated 

applications will not run as a result of this. 

Updating the Firmware (of the Operating System) in Modules and Submodules 

Offline 


A5E00706944-01 18-13



18-14 A5E00706944-01

19 Downloading and Uploading 

19.1 Downloading from the PG/PC to the Programmable 

Controller 

19.1.1 Requirements for Downloading 

Requirements for Downloading to the Programmable Controller 

• There must be a connection between your programming device and the CPU in 

the programmable controller (for example, via the multipoint interface). 

• Access to the programmable controller must be possible. 

• For the download of blocks to the PLC, the entry "STEP 7" must have been 

selected for "Use" in the object properties dialog of the project. 

• The program you are downloading has been compiled without errors. 

• The CPU must be in an operating mode in which downloading is permitted 

(STOP or RUN-P). 

Note that in RUN-P mode the program will be downloaded a block at a time. If 

you overwrite an old CPU program doing this, conflicts may arise, for example, 

if block parameters have changed. The CPU then goes into STOP mode while 

processing the cycle. We therefore recommend that you switch the CPU to 

STOP mode before downloading. 

• If you opened the block offline and want to download it, the CPU must be linked 

to an online user program in the SIMATIC Manager. 

• Before you download your user program, you should reset the CPU to ensure 

that no "old" blocks are on the CPU. 

STOP Mode 

Set the operating mode from RUN to STOP before you do the following: 

• Download the complete user program or parts of it to the CPU 

• Execute a memory reset on the CPU 

• Compress the user memory 


A5E00706944-01 19-1

Downloading and Uploading 

Restart (Warm Restart (Transition to RUN Mode) 

If you execute a restart (warm restart) in the "STOP" mode, the program is 

restarted and first processes the startup program (in the block OB100) in 

STARTUP mode. If the startup is successful, the CPU changes to RUN mode. A 

restart (warm restart) is required after the following: 

• Resetting the CPU 

• Downloading the user program in STOP mode 

19.1.2 Differences Between Saving and Downloading Blocks 

You should always distinguish between saving and downloading blocks. 

Menu commands 

Function 

Syntax check 

Saving 

File > Save 

File > Save As 

The current status of the block in the 

editor is saved on the hard disk of the 

programming device. 

A syntax check is run. Any errors are 

reported in dialog boxes. The causes of 

the errors and the error locations are also 

shown. You must correct these errors 

before you save or download the block. If 

no errors are found in the syntax, the 

block is compiled into machine code and 

either saved or downloaded. 

Downloading 

PLC > Download 

The current status of the block in the 

editor is only downloaded to the CPU. 

A syntax check is run. Any errors are 

reported in dialog boxes. The causes of 

the errors and the error locations are 

also shown. You must correct these 

errors before you save or download the 

block. If no errors are found in the 

syntax, the block is compiled into 

machine code and either saved or 

downloaded. 

The table applies independent of whether you have opened the block online or 

offline. 

Tip for Block Changes - Save First Then Download 

To enter newly created blocks or changes in the code section of logic blocks, in 

declaration tables or to enter new or changed data values in data blocks, you must 

save the respective block. Any changes you make in the editor and transfer to the 

CPU using the menu command PLC > Download, -for example, for testing small 

changes-, must also be saved on the hard disk of the programming device in every 

case before you exit the editor. Otherwise, you will have different versions of your 

user program in the CPU and on the programming device. It is generally 

recommended that you save all changes first and then download them. 


19-2 A5E00706944-01


19.1.3 Load Memory and Work Memory in the CPU 

After completing the configuration, parameter assignment, and program creation 

and establishing the online connection, you can download complete user programs 

or individual blocks to a programmable controller. To test individual blocks, you 

must download at least one organization block (OB) and the function blocks (FB) 

and functions (FC) called in the OB and the data blocks (DB) used. To download 

the system data created when the hardware was configured, the networks 

configured, and the connection table created to the programmable controller, you 

download the object "System Data". 

You download user programs to a programmable controller using the SIMATIC 

Manager, for example, during the end phase of the program testing or to run the 

finished user program. 

Relationship - Load Memory and Work Memory 

The complete user program is downloaded to the load memory; the parts relevant 

to program execution are also loaded into the work memory. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CPU Load Memory 

• The load memory is used to store the user program without the symbol table 

and the comments (these remain in the memory of the programming device). 

• Blocks that are not marked as required for startup will be stored only in the load 

memory. 

• The load memory can either be RAM, ROM, or EPROM memory, depending on 

the programmable controller. 

• The load memory can also have an integrated EEPROM part as well as an 

integrated RAM part (for example, CPU 312 IFM and CPU 314 IFM). 

• In S7-400, it is imperative that you use a memory card (RAM or EEPROM) to 

extend the load memory. 


A5E00706944-01 19-3


CPU Work Memory 

The work memory (integrated RAM) is used to store the parts of the user program 

required for program processing. 

Possible Downloading/Uploading Procedures 

• You use the download function to download the user program or loadable 

objects (for example, blocks) to the programmable controller. If a block already 

exists in the RAM of the CPU, you will be prompted to confirm whether or not 

the block should be overwritten. 

• You can select the loadable objects in the project window and download them 

from the SIMATIC Manager (menu command: PLC > Download). 

• When programming blocks and when configuring hardware and networks you 

can directly download the object you were currently editing using the menu in 

the main window of the application you are working with (menu command: PLC 

> Download). 

• Another possibility is to open an online window with a view of the programmable 

controller (for example, using View > Online or PLC > Display Accessible 

Nodes) and copy the object you want to download to the online window. 

Alternatively you can upload the current contents of blocks from the RAM load 

memory of the CPU to your programming device via the load function. 

19.1.4 Download Methods Dependent on the Load Memory 

The division of the load memory of a CPU into RAM and EEPROM areas 

determines the methods available for downloading your user program or the blocks 

in your user program. The following methods are possible for downloading data to 

the CPU: 

Load Memory Method of Loading Type of Communication 

between PG and PLC 

RAM 

Downloading and deleting individual Online PG - PLC connection 

blocks 

Downloading and deleting a Online PG - PLC connection 

complete user program 

Reloading individual blocks Online PG - PLC connection 

Integrated (S7-300 only) or 

plug-in EPROM 

Plug-in EPROM 

Downloading complete user 

programs 

Downloading complete user 

programs 

Online PG - PLC connection 

External loading of the EPROM 

and inserting the memory card or 

via online connection on the PLC 

where the EPROM is inserted. 

Downloading to the RAM via Online Connection 

In the programmable controller the data are lost if there is a power failure and the 

RAM is not backed up. The data in the RAM will then be lost in this case. 


19-4 A5E00706944-01


Saving to EPROM Memory Card 

Blocks or the user program are saved on an EPROM memory card which is then 

inserted in a slot on the CPU. 

Memory cards are portable data media. They are written by the programming 

device and then inserted in the appropriate slot on the CPU. 

The data stored on them are retained following power down and when the CPU is 

reset. The contents of the EPROM are copied to the RAM area of the CPU memory 

again when power returns following a memory reset of the CPU and power down if 

the RAM is not backed up. 

Saving in the Integrated EPROM 

For the CPU 312, you can also save the contents of the RAM to the integrated 

EPROM. The data in the integrated EPROM are retained during power down. The 

contents of the integrated EPROM are copied to the RAM area of the CPU memory 

again when power returns following power down and a memory reset of the CPU if 

the RAM is not backed up. 

19.1.5 Downloading a Program to the S7 CPU 

19.1.5.1 Downloading with Project Management 

1. In the project window, select the user program or the blocks you want to 

download. 

2. Download the selected objects to the programmable logic controller by 

selecting the menu command PLC > Download. 

Alternative Procedure (Drag & Drop) 

1. Open an offline window and an online window of your project. 

2. Select the objects you want to download in the offline window and drag them to 

the online window. 


A5E00706944-01 19-5


19.1.5.2 Downloading without Project Management 

1. Open the "Accessible Nodes" window using the menu command PLC > 

Display Accessible Nodes or by clicking the corresponding button in the 

toolbar. 

2. Double-click in the "Accessible Nodes" window on the required node 

("MPI=...") to display the "Blocks" folder. 

3. Open the library or the project from which you want to download the user 

program or blocks to the programmable logic controller. Use the menu 

command File > Open for this. 

4. In the window which opens for the project or the library, select the objects you 

want to download. 

5. Download the objects to the programmable logic controller by copying them to 

the "Blocks" folder in the "Accessible Nodes" window using drag & drop. 

19.1.5.3 Reloading Blocks in the Programmable Controller 

You can overwrite blocks which already exist in the load memory (RAM) or work 

memory of the CPU in the S7 programmable logic controller with a new version 

(reload them). The existing version is then overwritten. 

The procedure for reloading S7 blocks is the same as for downloading. A prompt 

simply appears, querying whether you want to overwrite the existing block. 

A block stored in the EPROM cannot be deleted but is declared invalid once it is 

reloaded. The replacement block is loaded in the RAM. This creates gaps in the 

load memory or the work memory. If these gaps eventually mean that no new 

blocks can be downloaded, you should compress the memory. 

Note 

If the power goes down and then returns and the RAM does not have a battery 

backup, or following a memory reset of the CPU the "old" blocks become valid 

again. 


19-6 A5E00706944-01


19.1.5.4 Saving Downloaded Blocks on Integrated EPROM 

For CPUs that have an integrated EPROM (such as CPU 312), you can save 

blocks from the RAM to the integrated EPROM so as not to lose the data following 

power off or memory reset. 

1. Use the menu command View > Online to display a window containing the 

online view of an open project or open the "Accessible Nodes" window by 

clicking the "Accessible Nodes" button in the toolbar or selecting the menu 

command PLC > Display Accessible Nodes. 

2. Select the S7 or M7 program in the online window of the project or the node in 

the "Accessible Nodes" window. 

3. Select the "Blocks" folder on the CPU which you want to save using one of the 

following methods: 

- In the online window of the project if you are working with project 

management 

- In the "Accessible Nodes" window if you are working without project 

management 

4. Select the menu command PLC > Save RAM to ROM. 

19.1.5.5 Downloading via EPROM Memory Cards 

Requirements 

For access to EPROM memory cards in the programming device which are 

intended for an S7 programmable logic controller, you will require the appropriate 

EPROM drivers. For access to EPROM memory cards which are intended for an 

M7 programmable control system, the Flash File System must be installed (only 

possible on the PG 720, PG 740, and PG 760). EPROM drivers and the Flash File 

System are offered as options when you install the STEP 7 Standard package. If 

you are using a PC, an external prommer will be required to save to EPROM 

memory cards. 

You can also install the drivers at a later date. To do this, call up the corresponding 

dialog box via Start > Simatic > STEP 7 > Memory Card Parameter Assignment 

or via the Control Panel (double-click the "Memory Card Parameter Assignment" 

icon). 


A5E00706944-01 19-7


Saving on the Memory Card 

To save blocks or user programs to a memory card, proceed as follows: 

1. Insert the memory card in the slot of your programming device. 

2. Open the "Memory Card" window by: 

- Clicking the button for "Memory Card" in the toolbar. If necessary, activate 

the toolbar using the menu command View > Toolbar. 

- Alternatively, select the menu command File > S7 Memory Card > Open. 

3. Open or activate one of the following windows displaying the blocks you want 

to save: The following windows are possible: 

- Project window, "ONLINE" view 

- Project window, "offline" view 

- Library window 

- "Accessible Nodes" window 

4. Select the "Blocks" folder or individual blocks and copy them to the "S7 

Memory Card" window. 

5. If a block already exists on the memory card, an error message is displayed. In 

this case, erase the contents of the memory card and repeat the steps from 2. 


19-8 A5E00706944-01


19.2 Compiling and Downloading Several Objects from the 

PG 

19.2.1 Requirements for and Notes on Downloading 

Downloading Block Folders 

For block folders, only logic blocks can be downloaded. Other objects in the block 

folder, such as system data (SDBs), etc. cannot be downloaded here. SDBs are 

downloaded through the "Hardware" object. 

Note 

For PCS 7 projects, blocks cannot be downloaded using the dialog "Compile and Download 

Objects"- just as they cannot be downloaded from the SIMATIC Manager. For PCS 7 

projects, the following applies: PLCs must only be downloaded to by means of CFCs in 

order to ensure correct sequencing during the download. This must be done to prevent the 

CPU from going into STOP mode. 

To determine whether the given project is a PCS 7 project, check the project properties. 

Downloading the F-Shares of Failsafe Controllers 

For security reasons, a password must be entered before modified F-shares can 

be downloaded. For this reason, with the "Compile and Download Objects" 

function, the download procedure will be aborted with an error message. In this 

case, load the appropriate parts of the program along with the optional package to 

the PLC. 

Downloading the Hardware Configuration 

Downloading the hardware configuration (i.e. downloading the offline SDBs) by 

means of the "Compile and Download Objects" function will only run without 

interruption for all selected objects if no error messages or prompts are triggered. 

The following section provides information on how to avoid such messages or 

prompts. 


A5E00706944-01 19-9


Requirements for Downloading the Hardware Configuration 

• CPUs must be in STOP mode. 

• It must be possible to establish online connections to the CPUs. In the case of 

the selected CPU or the selected block folder, password-projected CPUs 

require an authorized connection or entry of a password ("Edit" button) before 

the "Compile and Download Objects" function can be run. 

• The interface of the target system that is being used for downloading must not 

be reconfigured to any substantial extent: 

- The interface address must not be changed. 

- If you change the network settings, this may mean that not all the modules 

will be able to be accessed. 

• In the case of H-CPUs, you can select the CPU to receive the download (H- 

CPU 0 or H-CPU 1) before running the "Compile and Download Objects" 

function (Select the "CPU" object and then click the "Edit" button). 

• The following CPU parameters must not be changed: 

- The maximum size for local data and communications resources on the 

CPU ("Memory" tab) 

- The password protection for the F-CPU ("Protection" tab) 

• For each configured module, the following conditions must be fulfilled: 

- The order number for the configured module must be identical with the 

order number of the module that is actually inserted. 

- The firmware version of the configured module must not be higher than the 

firmware version of the module that is actually inserted. 

- The station name, the name of the module and the plant designation must 

not have changed since the last download. However, you can assign a 

new plant designation. 

Tips on the Download Procedure 

• All offline SDBs will be downloaded (that is, in addition to the hardware 

configuration, also the connection SDBs and SDBs that were created through 

global data configurations). 

• Downloading is only carried out if no errors occurred during the previous 

compilation process. 

• During the download, any error feedback messages are suppressed. For 

example, if a CPU memory bottleneck occurs, the data will be compressed 

automatically without the user being informed. 

• After the download is complete, the downloaded modules will be in STOP mode 

(except for those modules that are automatically stopped and restarted without 

the user being informed). 

Tip 

If, after the download is completed, a message appears stating that the download 

of the object was completed with warnings, then be sure to view the contents of the 

log. It may be that the object was either not downloaded or was not downloaded 

completely. 


19-10 A5E00706944-01


19.2.2 Compiling and Downloading Objects 

In the "Compile and download objects" dialog you prepare the objects that can be 

selected in your project or multiproject for transfer to the PLC and their subsequent 

download (if desired). This dialog can be used for objects in a station, a project or a 

multiproject. 

Depending on the object selected, certain information may not be displayed. In 

addition, not all the functions described below may be available for these objects. 

In particular, these restrictions may apply to objects that were created with optional 

software packages. 

For blocks in a block folder "compile" means that the consistency of the blocks is 

checked. In the following, for simplicity, the consistency check for blocks will be 

referred to as compilation. 

Procedure: 

1. In SIMATIC Manager, select the object that you want to compile, or compile 

and download. The following objects can be selected in the SIMATIC Manager: 

- Multiproject 

- Project 

- Station 

- S7 program without station assignment 

2. In the SIMATIC Manager, select menu command PLC > Compile And 

Download Objects. 

3. Select "Only compile" if you want to perform a check of the blocks without 

downloading them to the PLC. Select this option if you do not want to download 

any of these objects to the PLC 

4. To prevent incomplete downloads to stations due to compilation errors, select 

the check box "No download on compilation error". If this check box is 

selected, nothing will be downloaded. If the check box is not selected, then all 

objects compiled without error are downloaded. Objects that caused an error 

during compilation are not downloaded. 

5. If you want to compile and download connections, select the corresponding 

check box for the "Connections" object. 

6. A multiproject is particularly suited for use as a starting point, since all 

connection partners for cross-project connections can also be downloaded 

from this object. 

7. In the "Compile" and "Download" columns, select the objects that you want to 

compile or download. You selections will be indicated by checkmarks. If you 

selected "Compile only" in Step 3, the "Download" column will be grayed out 

and unavailable. 

8. Click on "Start" to begin the compilation. 


A5E00706944-01 19-11


9. Follow the instructions on the screen. 

After the compilation or download is complete, a full log is displayed. You can open 

the full log or single-object log at any time: 

• Click on the "All" button to view the full log of the complete action. 

• Click on "Single object" button to view only the log of the object you have 

selected in the object table. 

Special considerations when compiling and downloading connections 

If, in a module, you select the "Connections" object as the one to be compiled, 

then STEP 7 automatically selects the corresponding "Connections" object in the 

connection partner. By doing this, STEP 7 always creates consistent configuration 

data (system data blocks). The automatically selected objects cannot be directly 

deselected manually. However, the selection is automatically removed if the 

originally selected "Connections" object is also deselected. 

If, in a module, you select the "Connections" object as the one to be downloaded, 

then STEP 7 automatically selects the "Compile" check box. In addition, STEP 7 

also selects the "Compile" and "Download" check boxes for all connection partners. 

If only objects of the "Connections" type were selected, you can also download the 

connections when the CPU is in RUN-P operating mode. 

You can use NetPro to download individual connections. 

Compiling and downloading hardware: effects on connections 

If you select the "Hardware" object as the one to be compiled or downloaded, all 

"Connections" objects below the hardware selected are also automatically selected 

to be compiled or downloaded. In this case, however, the connection objects at the 

connections partners are not automatically selected as well! 


19-12 A5E00706944-01


19.3 Uploading from the Programmable Controller to the 

PG/PC 

This function supports you when carrying out the following actions: 

• Saving information from the programmable controller (for example, for servicing 

purposes) 

• Fast configuring and editing of a station, if the hardware components are 

available before you start configuring. 

Saving Information from the Programmable Controller 

This measure may be necessary if, for example, the offline project data of the 

version running on the CPU are not, or only partially, available. In this case, you 

can at least retrieve the project data that are available online and upload them to 

your programming device. 

Fast Configuring 

Entering the station configuration is easier if you upload the configuration data from 

the programmable controller to your programming device after you have configured 

the hardware and restarted (warm restart) the station. This provides you with the 

station configuration and the types of the individual modules. Then all you have to 

do is specify these modules in more detail (order number) and assign them 

parameters. 

The following information is uploaded to the programming device: 

• S7-300: Configuration for the central rack and any expansion racks 

• S7-400: Configuration of the central rack with a CPU and signal modules 

without expansion racks 

• Configuration data for the distributed I/O cannot be uploaded to the 


This information is uploaded if there is no configuration information on the 

programmable controller; for example, if a memory reset has been carried out on 

the system. Otherwise, the Upload function provides much better results. 

For S7-300 systems without distributed I/O, all you have to do is specify these 

modules in more detail (order number) and assign them parameters. 

Note 

When you upload data (if you do not already have an offline configuration), STEP 7 

cannot determine all the order numbers of the components. 

You can enter the "incomplete" order numbers when you configure the hardware 

using the menu command Options > Specify Module. In this way, you can assign 

parameters to modules that STEP 7 does not recognize (that is, modules that do 

not appear in the "Hardware Catalog" window); however, STEP 7 will not then 

check whether you are keeping to the parameter rules. 


A5E00706944-01 19-13


Restrictions when Uploading from the Programmable Controller 

The following restrictions apply to the data uploaded from the programmable 

controller to the programming device: 

• Blocks do not contain any symbolic names for parameters, variables, and labels 

• Blocks do not contain any comments 

• The entire program is uploaded with all the system data, whereby the system 

can only continue to process the system data belonging to the "Configuring 

Hardware" application 

• The data for global data communication (GD) and configuring symbol-related 

messages cannot be processed further 

• Force jobs are not uploaded to the programming device with the other data. 

They must be saved separately as a variable table (VAT) 

• Comments in the module dialog boxes are not uploaded 

• The names of the modules are only displayed if this option has been selected 

during configuration (HW Config: the option "Save object names in the 

programmable logic controller" in the dialog box under Options > Customize). 

19.3.1 Uploading a Station 

Using the menu command PLC > Upload Station you can upload the current 

configuration and all blocks from the programmable controller of your choice to the 


To do this, STEP 7 creates a new station in the current project under which the 

configuration will be saved. You can change the preset name of the new station 

(for example, "SIMATIC 300-Station(1)"). The inserted station is displayed both in 

the online view and in the offline view. 

The menu command can be selected when a project is open. Selecting an object in 

the project window or the view (online or offline) has no effect on the menu 

command. 

You can use this function to make configuring easier. 

• For S7-300 programmable controllers, the configuration for the actual hardware 

configuration is uploaded including the expansion racks, but without the 

distributed I/O (DP). 

• For S7-400 programmable controllers, the rack configuration is uploaded 

without the expansion racks and without the distributed I/O. 

With S7-300 systems without distributed I/O, all you have to do is specify the 

modules in more detail (order number) and assign them parameters. 


19-14 A5E00706944-01


Restrictions when Uploading Stations 

The following restrictions apply to the data uploaded to the programming device: 

• Blocks do not contain any symbolic names for parameters, variables, and labels 

• Block do not contain any comments 

• The entire program is uploaded with all the system data, whereby not all the 

data can be processed further 

• The data for global data communication (GD), configuring symbol-related 

messages, and configuring networks cannot be processed further 

• Force jobs cannot be uploaded to the programming device and then loaded 

back to the programmable controller. 

19.3.2 Uploading Blocks from an S7 CPU 

You can upload S7 blocks from the CPU to the hard disk of the programming 

device using the SIMATIC Manager. Uploading blocks to the programming device 

is useful in the following situations: 

• Making a backup copy of the current user program loaded in the CPU. This 

backup can then be downloaded again, for example, following servicing or 

following a memory reset of the CPU by maintenance personnel. 

• You can upload the user program from the CPU to the programming device and 

edit it there, for example, for troubleshooting purposes. In this case you do not 

have access to symbols or comments for program documentation. Therefore we 

recommend that this procedure is used only for service purposes. 


A5E00706944-01 19-15


19.3.3 Editing Uploaded Blocks in the PG/PC 

Being able to upload blocks from the CPU to the programming device has the 

following uses: 

• During the test phase, you can correct a block directly on the CPU and 

document the result. 

• You can upload the current contents of blocks from the RAM load memory of 

the CPU to your programming device via the load function. 

Note 

Time stamp Conflicts when Working Online and Offline 

The following procedures lead to time stamp conflicts and should therefore be 

avoided. 

Time stamp conflicts result when you open a block online if: 

• Changes made online were not saved in the offline S7 user program 

• Changes made offline were not downloaded to the CPU 

Time stamp conflicts result when you open a block offline if: 

• An online block with a time stamp conflict is copied to the S7 user program 

offline and the block is then opened offline. 

Two Distinct Cases 

When uploading blocks from the CPU to the programming device, remember that 

there are two distinct situations: 

1. The user program to which the blocks belong is located on the programming 

device. 

2. The user program to which the blocks belong is not on the programming 

device. 

This means that the program sections listed below, that cannot be downloaded to 

the CPU, are not available. These components are: 

• The symbol table with the symbolic names of the addresses and the comments 

• Network comments of a Ladder Logic or Function Block Diagram program 

• Line comments of a Statement List program 

• User-defined data types 


19-16 A5E00706944-01


19.3.3.1 Editing Uploaded Blocks if the User Program is on the PG/PC 

To edit blocks from the CPU, proceed as follows: 

1. Open the online window of the project in the SIMATIC Manager. 

2. Select a "Blocks" folder in the online window. The list of loaded blocks is 

displayed. 

3. Now select the blocks, open and edit them. 

4. Select the menu command File > Save to save the change offline on the 


5. Select the menu command PLC > Download to download the changed blocks 

to the programmable controller. 

19.3.3.2 Editing Uploaded Blocks if the User Program is Not on the 

PG/PC 

To edit blocks from the CPU, proceed as follows: 

1. In the SIMATIC Manager, click the "Accessible Nodes" toolbar button or select 

the menu command PLC > Display Accessible Nodes. 

2. Select the node ("MPI=..." object) from the list displayed and open the "Blocks" 

folder to display the blocks. 

3. You can now open blocks and edit, monitor, or copy them as required. 

4. Select the menu command File > Save As and enter the path for the 

programming device where you want to store the blocks in the dialog box. 

5. Select the menu command PLC > Download to download the changed blocks 

to the programmable controller. 


A5E00706944-01 19-17


19.4 Deleting on the Programmable Controller 

19.4.1 Erasing the Load/Work Memory and Resetting the CPU 

Before downloading your user program to the S7 programmable controller, you 

should perform a memory reset on the CPU to ensure that no "old" blocks are still 

on the CPU. 

Requirement for Memory Reset 

The CPU must be in STOP mode to perform a memory reset (mode selector set to 

STOP, or to RUN-P and change the mode to STOP using the menu command 

PLC > Diagnostics/Settings > Operating Mode). 

Performing a Memory Reset on an S7 CPU 

When a memory reset is performed on an S7 CPU, the following happens: 

• The CPU is reset. 

• All user data are deleted (blocks and system data blocks (SDB) with the 

exception of the MPI parameters). 

• The CPU interrupts all existing connections. 

• If data are present on an EPROM (memory card or integrated EPROM), the 

CPU copies the EPROM contents back to the RAM area of the memory 

following the memory reset. 

The contents of the diagnostic buffer and the MPI parameters are retained. 

Performing a Memory Reset on M7 CPUs/FMs 

When a memory reset is performed on an M7 CPU/FM, the following happens: 

• The original state is restored. 

• The system data blocks (SDB) with the exception of the MPI parameters are 

deleted. 

• The CPU/FM breaks off all existing connections. User programs are retained 

and will continue running after you switch the CPU from STOP to RUN. 

With the "memory reset" function you can restore the original state of the M7 CPU 

or FM following serious errors by deleting the current system data blocks (SDB) 

from the work memory and reloading the SDBs in the read-only memory. In some 

cases, a warm restart of the operating system will be required. To do this, you clear 

the M7 using the mode selector (switch to MRES position). A reset using the mode 

selector on SIMATIC M7 CPUs or FMs is only possible if the RMOS32 operating 

system is used on the CPU/FM. 


19-18 A5E00706944-01


19.4.2 Deleting S7 Blocks on the Programmable Controller 

Deleting individual blocks on the CPU may be necessary during the test phase of 

the CPU program. Blocks are stored in the user memory of the CPU either in the 

EPROM or RAM (depending on the CPU and the load procedure). 

• Blocks in the RAM can be deleted directly. The occupied space in the load or 

work memory becomes free and can be used again. 

• Blocks in the integrated EPROM are always copied to the RAM area following a 

memory reset of the CPU. The copies in the RAM can be deleted directly. The 

deleted blocks are then marked in the EPROM as invalid until the next memory 

reset or power down without RAM backup. Following a memory reset or power 

down without RAM backup, the "deleted" blocks are copied from the EPROM to 

the RAM and become active. Blocks in the integrated EPROM (for example, in 

the CPU 312) are deleted by overwriting them with the new RAM contents. 

• EPROM memory cards must be erased in the programming device. 


A5E00706944-01 19-19


19.5 Compressing the User Memory (RAM) 

19.5.1 Gaps in the User Memory (RAM) 

After deleting and reloading blocks, gaps can occur in the user memory (load and 

work memory) and reduce the usable memory area. With the compress function, 

the existing blocks are rearranged in the user memory without gaps, and a 

continuous free memory is created. 

The following figure shows a diagram of how occupied blocks of memory are 

shifted together by the compress function. 

 

 

 

 

Always Try to Compress the Memory in STOP Mode 

Only if you compress the memory in "STOP" mode are all the gaps closed up. In 

the RUN-P mode (mode selector setting), the blocks currently being processed 

cannot be shifted since they are open. The compress function does not work in the 

RUN mode (mode selector setting) (write protection!). 


19-20 A5E00706944-01


19.5.2 Compressing the Memory Contents of an S7 CPU 

Ways of Compressing the Memory 

There are two methods of compressing the user memory, as follows: 

• If there is insufficient memory available when you are downloading to the 

programmable controller, a dialog box appears informing you of the error. You 

can compress the memory by clicking the corresponding button in the dialog 

box. 

• As a preventative measure, you can display the memory utilization (menu 

command PLC > Diagnostics/Setting > Module Information, "Memory" tab) 

and start the compressing function if required. 

Procedure 

1. Select the S7 program in the "Accessible Nodes" window or the online view of 

the project. 

2. Select the menu command PLC > Diagnostics/Setting > Module Information. 

3. In the dialog box which then appears, select the "Memory" tab. In this tabbed 

page there is a button for compressing the memory if the CPU supports this 

function. 


A5E00706944-01 19-21



19-22 A5E00706944-01

20 Testing with the Variable Table 

20.1 Introduction to Testing with Variable Tables 

Variable tables offer the advantage of being able to store various test 

environments. Thus, tests and monitoring can be effortlessly reproduced during 

operation or for the purpose of service and maintenance. There is no limit to the 

number of variable tables that can be stored. 

When testing using variable tables, the following functions are available: 

• Monitoring Variables 

This function enables you to display on the programming device/PC the current 

values of individual variables in a user program or a CPU. 

• Modifying Variables 

You can use this function to assign fixed values to individual variables of a user 

program or a CPU. Modifying values once and immediately is also possible 

when testing using program status. 

• Enable Peripheral Output and Activate Modify Values 

These two functions allow you to assign fixed values to individual I/O outputs of 

a CPU in STOP mode. 

• Forcing Variables 

You can use this function to assign individual variables of a user program or a 

CPU with a fixed value that cannot be overwritten by the user program. 

You can assign or display the values for the following variables: 

• Inputs, outputs, bit memory, timers, and counters 

• Contents of data blocks 

• I/O (periphery) 

You enter the variables you want to display or modify in variable tables. 

You can determine when and how often the variables are monitored or assigned 

new values by defining a trigger point and trigger frequency. 


A5E00706944-01 20-1

Testing with the Variable Table 

20.2 Basic Procedure when Monitoring and Modifying with 

the Variable Table 

To use the Monitor and Modify functions, proceed as follows: 

1. Create a new variable table or open an existing variable table. 

2. Edit or check the contents of the variable table. 

3. Establish an online connection between the current variable table and the 

required CPU using the menu command PLC > Connect To. 

4. Using the menu command Variable > Trigger, select a suitable trigger point 

and set the trigger frequency. 

5. The menu commands Variable > Monitor and Variable > Modify toggle the 

Monitor and Modify functions on and off. 

6. Save the completed variable table using the menu command Table > Save or 

Table > Save As, so that you can call it up again at any time. 


20-2 A5E00706944-01


20.3 Editing and Saving Variable Tables 

20.3.1 Creating and Opening a Variable Table 

Before you can monitor or modify variables, you must create a variable table (VAT) 

and enter the required variables. To create a variable table, you can choose from 

one of the following methods: 

In the SIMATIC Manager: 

• Select the "Blocks" folder and the menu command Insert > S7 Block > 

Variable Table. In the dialog box, you can give the table a name ("Symbolic 

Name" text box). You can open the variable table by double-clicking the object. 

• Select a connection or, in the online view, an S7 or M7 program from the list of 

accessible nodes. You create an unnamed variable table using the menu 

command PLC > Monitor/Modify Variables. 

In "Monitor/Modify Variables": 

• You can use the menu command Table > New to create a new variable table 

which is not yet assigned to any S7 or M7 program. You can open existing 

tables with Table > Open. 

• You can use the corresponding symbols in the toolbar to create or open 

variable tables. 

Once you have created a variable table, you can save it, print it out, and use it 

again and again for monitoring and modifying. 

20.3.2 Copying/Moving Variable Tables 

You can copy or move variable tables in block folders of an S7/M7 program. 

Note the following when copying or moving variable tables: 

• Existing symbols in the symbol table of the target program will be updated. 

• When you move a variable table, the corresponding symbols from the symbol 

table of the source program will also be moved to the symbol table of the target 

program. 

• When you delete variable tables from the block folder, the corresponding 

symbols from the symbol table of the S7/M7 program will also be deleted. 

• If the target program already contains a variable table with the same name, the 

next-highest free number will be assigned when you copy the variable table. 

• If the target program already contains a variable table with the same name, you 

can rename the variable table when copying (as a default a number is attached 

to the existing name). 


A5E00706944-01 20-3


20.3.3 Saving a Variable Table 

You can use saved variable tables to monitor and modify variables when you test a 

program again. 

1. Save the variable table using the menu command Table > Save. 

2. If the variable table has been created, you must now give the variable table a 

name, for example, "ProgramTest_1." 

When you save a variable table, all the current settings and the table format are 

saved. This means that the settings made under the menu item "Trigger" are 

saved. 

20.4 Entering Variables in Variable Table 

20.4.1 Inserting Addresses or Symbols in a Variable Table 

Select the variables whose values you want to modify or monitor and enter them in 

the variable table. Start from the "outside" and work "inwards"; this means you 

should first select the inputs and then the variables that are influenced by the 

inputs and which influence the outputs, and finally the outputs. 

If you want, for example, to monitor the input bit 1.0, the memory word 5, and the 

output byte 0, enter the following in the "Address" column: 

Example: 

I 1.0 

MW5 

QB0 


20-4 A5E00706944-01


Example of a Completed Variable Table 

The following figure shows a variable table with the following visible columns: 

Address, Symbol, Display Format, Monitor Value, and Modify Value 

Notes on Inserting Symbols 

• You enter the variable you want to modify with your address or as a symbol. 

You can enter symbols and addresses either in the "Symbol" column or in the 

"Address" column. The entry is then written automatically in the correct column. 

If the corresponding symbol is defined in the symbol table, the symbol column 

or the address column is filled out automatically. 

• You can enter only those symbols that are already defined in the symbol table. 

• You must enter a symbol exactly as it is defined in the symbol table. 

• Symbol names that contain special characters must be enclosed in quotation 

marks (for example, "Motor.Off," "Motor+Off," "Motor-Off"). 

• To define new symbols in the symbol table select the menu command Options 

> Symbol Table. Symbol can also be copied from the symbol table and pasted 

in a variable table. 


A5E00706944-01 20-5


Syntax Check 

When you enter variables in the variable table, a syntax check is carried out at the 

end of each line. Any incorrect entries are marked in red. 

If you position the cursor in a row marked in red, a brief information is displayed 

telling you the cause of the error. Notes on correcting the error can be obtained by 

pressing F1. 

Note 

If you prefer to edit the variable table with the keyboard (without the mouse), you 

should keep the "Brief Information When Using the Keyboard" feature enabled. 

If necessary, you can change the setting in the variable table by selecting the 

menu command Option > Customize and then selecting the "General" tab. 

Maximum Size 

A maximum of 255 characters per line are permitted in a variable table. A carriage 

return into the next row is not possible. A variable table can have up to a maximum 

of 1024 rows. This is then its maximum size. 

20.4.2 Inserting a Contiguous Address Range in a Variable Table 

1. Open a variable table. 

2. Position the cursor in the row after which you want the range of contiguous 

addresses to be inserted. 

3. Select the menu command Insert > Range of Variables. The "Insert Range of 

Variables" dialog box appears. 

4. Enter an address as the start address in the "From Address" field. 

5. Enter the number of rows to be inserted in the "Number" field. 

6. Select the required display format from the list displayed. 


The range of variables is inserted in the variable table. 


20-6 A5E00706944-01


20.4.3 Inserting Modify Values 

Modify Value as Comment 

If you want to make the "modify value" of a variable ineffective, use the Variable > 

Modify Value as Comment menu command. A comment marker "//" before the 

value to be modified of a variable indicates that it is without effect. The command 

marker "//" can also be inserted in front of the "modify value" instead of the menu 

command call. The ineffectiveness of the "modify value" can be reversed by 

calling up the Variable > Modify Value as Comment menu command again or by 

removing the comment marker. 

20.4.4 Upper Limits for Entering Timers 

Note the following upper limits for entering timers: 

Example: W#16#3999 (maximum value in BCD format) 

Examples: 

Address 

Monitor 

Format 

Enter 

Modify Value 

Display 

Explanation 

T 1 SIMATIC_TIME 137 S5TIME#130MS Conversion to milliseconds 

MW4 SIMATIC_TIME 137 S5TIME#890MS Representation in BCD format possible 

MW4 HEX 137 W#16#0089 Representation in BCD format possible 

MW6 HEX 157 W#16#009D Representation in BCD format not 

possible, therefore the monitor format 

SIMATIC_TIME cannot be selected 

Note 

• You can enter timers in millisecond steps but the value entered is adapted to 

the time frame. The size of the time frame depends on the size of the time 

value entered (137 becomes 130 ms; the 7 ms were rounded down). 

• The modify values for addresses of the data type WORD, for example, IW1, 

are converted to BCD format. Not every bit pattern is a valid BCD number, 

however. If the entry cannot be represented as SIMATIC_TIME for an address 

of the data type WORD, the application reverts automatically to the default 

format (here: HEX, see Select Monitor Format, Default Command (View 

Menu)) so that the value entered can be displayed. 


A5E00706944-01 20-7


BCD Format for Variables in the SIMATIC_TIME Format 

Values of variables in the SIMATIC_TIME format are entered in BCD format. 

The 16 bits have the following significance: 

| 0 0 x x | h h h h | t t t t | u u u u | 

Bits 15 and 14 are always zero. 

Bits 13 and 12 (marked with xx) set the multiplier for bits 0 to 11: 

00 => multiplier 10 milliseconds 

01 => multiplier 100 milliseconds 

10 => multiplier 1 second 

11 => multiplier 10 seconds 

Bits 11 to 8 hundreds (hhhh) 

Bits 7 to 4 tens (tttt) 

Bits 3 to 0 units (uuuu) 

20.4.5 Upper Limits for Entering Counters 

Note the following upper limits for entering counters: 

Upper limit for counters: C#999 

W#16#0999 (maximum value in BCD format) 

Examples: 

Address 

Monitor 

Format 

Enter 

Modify Value 

Display 

Explanation 

C1 COUNTER 137 C#137 Conversion 

MW4 COUNTER 137 C#89 Representation in BCD format 

possible 

MW4 HEX 137 W#16#0089 Representation in BCD format 

possible 

MW6 HEX 157 W#16#009D Representation in BCD format 

not possible, therefore the 

monitor format COUNTER 

cannot be selected 

Note 

• If you enter a decimal number for a counter and do not mark the value with C#, 

this value is automatically converted to BCD format (137 becomes C#137). 

• The modify values for addresses of the data type WORD, for example, IW1, 

are converted to BCD format. Not every bit pattern is a valid BCD number, 

however. If the entry cannot be represented as COUNTER for an address of 

the data type WORD, the application reverts automatically to the default format 

(here: HEX, see Select Monitor Format, Default Command (View Menu)) so 

that the value entered can be displayed. 


20-8 A5E00706944-01


20.4.6 Inserting Comment Lines 

Comment lines are introduced by the comment marker "//". 

If you want to make one or more lines of the variable table ineffective (as a 

comment line), use the Edit > Row not Effective menu command or the 

corresponding symbol 

in the toolbar. 

20.4.7 Examples 

20.4.7.1 Example of Entering Addresses in Variable Tables 

Permitted Address: Data Type: Example (English Mnemonics): 

Input | Output | Bit memory BOOL I 1.0 | Q 1.7 | M 10.1 

Input | Output | Bit memory BYTE IB 1 | QB 10 | MB 100 

Input | Output | Bit memory WORD IW 1 | QW 10 | MW 100 

Input | Output | Bit memory DWORD ID 1 | QD 10 | MD 100 

I/O (Input | Output) BYTE PIB 0 | PQB 1 

I/O (Input | Output) WORD PIW 0 | PQW 1 

I/O (Input | Output) DWORD PID 0 | PQD 1 

Timers TIMER T 1 

Counters COUNTER C 1 

Data block BOOL DB1.DBX 1.0 

Data block BYTE DB1.DBB 1 

Data block WORD DB1.DBW 1 

Data block DWORD DB1.DBD 1 

Note 

The entry "DB0. .." is not permitted because it is already used internally. 

In the Force Values Window 

• When forcing with S7-300 modules, only inputs, outputs, and I/O (outputs) are 

allowed. 

• When forcing with S7-400 modules, only inputs, outputs, bit memory, and I/O 

(inputs/outputs) are allowed. 


A5E00706944-01 20-9


20.4.7.2 Example of Entering a Contiguous Address Range 

Open a variable table and call up the "Insert Range of Variables" dialog box with 

the menu command Insert > Range of Variables. 

For the dialog box entries the following lines for bit memory are inserted in the 

variable table: 

• From address: M 3.0 

• Number: 10 

• Display format: BIN 

Address 

M 3.0 

M 3.1 

M 3.2 

M 3.3 

M 3.4 

M 3.5 

M 3.6 

M 3.7 

M 4.0 

M 4.1 

Display Format 

BIN 

BIN 

BIN 

BIN 

BIN 

BIN 

BIN 

BIN 

BIN 

BIN 

Note that in this example the designation in the "Address" column changes after 

the eighth entry. 


20-10 A5E00706944-01


20.4.7.3 Examples of Entering Modify and Force Values 

Bit Addresses 

Possible bit addresses Permitted modify/force values 

I1.0 true 

M1.7 false 

Q10.7 0 

DB1.DBX1.1 1 

I1.1 2#0 

M1.6 2#1 

Byte Addresses 

Possible byte addresses Permitted modify/force values 

IB 1 2#00110011 

MB 12 

b#16#1F 

MB 14 

1F 

QB 10 

'a' 

DB1.DBB 1 10 

PQB 2 -12 

Word Addresses 

Possible word addresses Permitted modify/force values 

IW 1 2#0011001100110011 

MW12 

w#16#ABCD 

MW14 

ABCD 

QW 10 

b#(12,34) 

DB1.DBW 1 

'ab' 

PQW 2 -12345 

MW3 12345 

MW5 

s5t#12s340ms 

MW7 0.3s or 0,3s 

MW9 c#123 

MW11 

d#1990-12-31 


A5E00706944-01 20-11


Double Word Addresses 

Possible double word 

Permitted modify/force values 

addresses 

ID 1 2#00110011001100110011001100110011 

MD 0 

23e4 

MD 4 2 

QD 10 

dw#16#abcdef10 

QD 12 

ABCDEF10 

DB1.DBD 1 

b#(12,34,56,78) 

PQD 2 

'abcd' 

MD 8 l# -12 

MD 12 l#12 

MD 16 -123456789 

MD 20 123456789 

MD 24 

t#12s345ms 

MD 28 

tod#1:2:34.567 

MD 32 

p#e0.0 

Timers 

Possible addresses of 

the type "Timer" 

Permitted modify/force 

values 

Explanation 

T 1 0 Conversion to milliseconds (ms) 

T 12 20 Conversion to ms 

T 14 12345 Conversion to ms 

T 16 

s5t#12s340ms 

T 18 3 Conversion to 1s 300 ms 

T 20 3s Conversion to 1s 300 ms 

Modifying a timer affects only the value, not the state. This means that the timer T1 

can be modified to the value 0, without the result of logic operation for A T1 being 

changed. 

The strings 5t, s5time can be written in either upper or lower case. 

Counters 

Possible addresses of the type 

Permitted modify/force values 

"Counter" 

C 1 0 

C 14 20 

C 16 c#123 

Modifying a counter only affects the value, not the state. This means that Counter 

C1 can be modified to the value 0 without the result of logic operation for A C1 

being changed. 


20-12 A5E00706944-01


20.5 Establishing a Connection to the CPU 

In order to be able to monitor or modify the variables you entered in your current 

variable table (VAT), you must establish a connection to the appropriate CPU. It is 

possible to link each variable table with a different CPU. 

Displaying an Online Connection 

If an online connection exists, the term "ONLINE" in the title bar of the variable 

table window indicates this fact. The status bar displays the operating states 

"RUN", "STOP", "DISCONNECTED" or "CONNECTED", depending on the CPU. 

Establishing an Online Connection to the CPU 

If an online connection to the required CPU does not exist, use the menu command 

PLC > Connect To > ... to define a connection to the required CPU so that 

variables can be monitored or modified. 

Interrupting the Online Connection to the CPU 

Using the menu command PLC > Disconnect you interrupt the connection 

between the variable table and the CPU. 

Note 

If you created an unnamed variable table with the menu command Table > New, 

you can establish a connection to the last configured CPU configured if it is 

defined. 


A5E00706944-01 20-13


20.6 Monitoring Variables 

20.6.1 Introduction to Monitoring Variables 

The following methods are available to you for monitoring variables: 

• Activate the Monitor function with the menu command Variable > Monitor. The 

values of the selected variables are displayed in the variable table in 

accordance with the trigger point and trigger frequency set. If you set the trigger 

frequency "Every cycle," you can toggle the Monitor function off again with the 

menu command Variable > Monitor. 

• You can update the values of the selected variables once and immediately 

using the menu command Variable > Update Monitor Values. The current 

values of the selected variables are displayed in the variable table. 

Aborting "Monitoring" with ESC 

If you press ESC while the "Monitoring" function is active, the function is terminated 

without a query. 

20.6.2 Defining the Trigger for Monitoring Variables 

You can display on the programming device the current values of individual 

variables in a user program at a specific point during program processing (trigger 

point) in order to monitor them. 

When you select a trigger point you determine the point in time at which the 

monitor values of variables will be displayed. 

You can set the trigger point and a trigger frequency using the menu command 

Variable > Trigger. 

Trigger 

Trigger point 

Trigger frequency 

Possible Settings 

Start of cycle 

End of cycle 

Transition from RUN to STOP 

Once 

Every cycle 


20-14 A5E00706944-01


Trigger Point 

The following figure shows the position of the trigger points. 

 

 

 

 

 

 

 

To display the modified value in the "Status Value" column, you should set the 

trigger point for monitoring to "Start of cycle" and the trigger point for modifying to 

"End of cycle". 

Trigger Immediately 

You can update the values of selected variables using the menu command 

Variable > Update Monitor Values. This command is taken to mean "trigger 

immediately" and is executed as quickly as possible without reference to any point 

in the user program. These functions are mainly used for monitoring and modifying 

in STOP mode. 

Trigger Frequency 

The following table shows the effect that the trigger frequency has on the 

monitoring of variables: 

Monitor 

Variables 

Trigger frequency: Once 

Update once 

Dependent on trigger point 

Trigger frequency: Every cycle 

Monitoring with a defined trigger 

When testing a block you can track the 

progress of processing exactly. 


A5E00706944-01 20-15


20.7 Modifying Variables 

20.7.1 Introduction to Modifying Variables 

The following methods are available to you for modifying variables: 

• Activate the Modify function with the menu command Variable > Modify. The 

user program applies the modify values for the selected variables from the 

variable table in accordance with the trigger point and trigger frequency set. If 

you set the trigger frequency "Every cycle," you can toggle the Modify function 

off again with the menu command Variable > Modify. 

• You can update the values of the selected variables once and immediately 

using the menu command Variable > Activate Modify Values. 

The functions Force and Enable Peripheral Output (PQ) provide other possibilities. 

When Modifying, Note: 

• Only those addresses that were visible in the variable table when you started 

modifying are modified. 

If you decrease the size of the visible area of the variable table once you have 

started modifying, addresses may be modified that are no longer visible. 

If the visible area of the variable table is made larger, there may be addresses 

visible that are not modified. 

• Modifying cannot be undone (for example, with Edit > Undo). 

! 

Danger 

Changing the variable values while a process is running can lead to serious 

damage to property or personnel if errors occur in the function or in the program. 

Make sure that no dangerous situations can occur before you execute the "Modify" 

function. 

Aborting "Modifying" with ESC 

If you press ESC while the "Modifying" function is in process, the function is 

aborted without a query. 


20-16 A5E00706944-01


20.7.2 Defining the Trigger for Modifying Variables 

You can assign fixed values to individual variables of a user program (once or 

every cycle) at a specific point during program processing (trigger point). 

When you select a trigger point you determine the point in time at which the modify 

values are assigned to the variables. 

You can set the trigger point and a trigger frequency using the menu command 

Variable > Trigger. 

Trigger 

Trigger point 

Trigger frequency 

Possible Settings 

Start of cycle 

End of cycle 

Transition from RUN to STOP 

Once 

Every cycle 

Trigger Point 

The following figure shows the position of the trigger points. 

 

 

 

 

 

 

 

The position of the trigger points shows: 

• Modifying inputs is only useful with the trigger point "Start of cycle" (corresponds 

to the start of the user program OB 1), because otherwise the process image of 

the inputs is updated after modifying and therefore overwritten). 

• Modifying outputs is only useful with the trigger point "End of cycle" 

(corresponds to the end of the user program OB 1), because otherwise the user 

program can overwrite the process image of the outputs). 


A5E00706944-01 20-17


To display the modified value in the "Status Value" column, you should set the 

trigger point for monitoring to "Start of cycle" and the trigger point for modifying to 

"End of cycle". 

The following applies to trigger points when modifying variables: 

• If you set "Once" as the trigger frequency, a message appears if the selected 

variables cannot be modified. 

• With the trigger frequency "Every cycle," no message appears. 

Trigger Immediately 

You can modify the values of selected variables using the menu command 

Variable > Activate Modify Values. This command is taken to mean "trigger 

immediately" and is executed as quickly as possible without reference to any point 

in the user program. This function is used mainly for modifying in STOP mode. 

Trigger Frequency 

The following table shows the effect that the trigger condition set has on the 

modifying of variables: 

Modify 

Variables 

Trigger frequency: Once 

Activate once 

You can assign values to 

variables once, independent of 

the trigger point. 

Trigger frequency: Every cycle 

Modifying with a defined trigger 

By assigning fixed values you can 

simulate certain situations for your user 

program and use this to debug the 

functions you have programmed. 


20-18 A5E00706944-01


20.8 Forcing Variables 

20.8.1 Safety Measures When Forcing Variables 

Beware of Injury to Personnel and Damage to Property 

Note that when using the "Force" function, any incorrect action could: 

• Endanger the life or health of personnel or 

• Cause damage to machines or the whole plant. 

! 

Caution 

• Before you start the Force function you should check that nobody is executing this 

function on the same CPU at the same time. 

• A Force job can only be deleted or terminated with the menu command Variable > 

Stop Forcing. Closing the force values window or exiting the "Monitoring and Modifying 

Variables" application does not delete the force job. 

• Forcing cannot be undone (for example, with Edit > Undo). 

• Read the information on the Differences between Forcing and Modifying Variables. 

• If a CPU does not support the Force function, all menu commands in the Variable menu 

linked with forcing are deactivated. 

If the output disable is deactivated with the menu command Variable > Enable Peripheral 

Output, all forced output modules output their force value. 


A5E00706944-01 20-19


20.8.2 Introduction to Forcing Variables 

You can assign fixed values to individual variables of a user program so that they 

cannot be changed or overwritten even by the user program executing in the CPU. 

The requirement for this is that the CPU supports this function (for example, the 

S7-400 CPUs). By assigning fixed values to variables you can set specific 

situations for your user program and use this to test the programmed functions. 

"Force Values" Window 

Only when the "Force Values" window is active can the menu commands for 

forcing be selected. 

To display this window, select the menu command Variable > Display Force 

Values. 

You should only open one single "Force Values" window for a CPU. The variables 

together with their respective force values for the active force job are displayed in 

this window. 

Example of a Force Values Window 

The name of the current online connection is shown in the title bar. 

The data and time the force job was read from the CPU are shown in the status 

bar. 

If no force job is active, the window is empty. 

The different methods of displaying variables in the "Force Values" window have 

the following significance: 

Display 

Bold: 

Normal: 

Grayed out: 

Meaning 

Variables that are already assigned a fixed value in the CPU. 

Variables that are being edited. 

Variables of a module that is not present/inserted in the rack 

or 

Variables with an address error; an error message is displayed. 


20-20 A5E00706944-01


Using Forcible Addresses from the Variable Table 

If you want to enter a variable from a variable table in the force value window, 

select the table and the required variable. Next, call menu command Variable > 

Force values to open the force value window. The variables a module can force 

will be entered in the force value window. 

Using the Force Job from the CPU or Setting Up a New Force Job 

If the "Force Values" window is open and active, another message is displayed: 

• If you confirm it, the changes in the window are overwritten with the force job 

existing on the CPU. You can restore the previous window contents with the 

menu command Edit > Undo. 

• If you cancel it, the current contents of the window are retained. 

You can then save the contents of the "Force Values" window as a variable 

table using the menu command Table > Save As or select the menu command 

Variable > Force: this writes the current contents of the window to the CPU as 

the new force job. 

Monitoring and modifying variables is only possible in the variable table and not in 

the "Force Values" window. 

Deleting Force Values 

Call menu command Variable > Display Force Values to open the force value 

window. Next, you can call menu command Variable > Delete Force to delete the 

force values from the selected CPU. 

Saving a Force Values Window 

You can save the contents of the force values window in a variable table. Using the 

Insert > Variable Table menu command, you can reinsert the saved contents in a 

force values window. 

Notes on Symbols in the Force Values Window 

The symbols in the last active window are entered except if you opened the 

"Monitoring and Modifying Variables" application from another application which 

has no symbols. 

If you cannot enter symbolic names, the "Symbol" column is hidden. The menu 

command Options > Symbol Table is deactivated in this case. 


A5E00706944-01 20-21


20.8.3 Differences Between Forcing and Modifying Variables 

The following table summarizes the differences between forcing and modifying: 

Feature / Function 

Forcing with 

S7-400 (incl. 

CPU 318-2DP) 

Forcing with 

S7-300 (without 

CPU 318-2DP) 

Bit memory (M) yes − yes 

Timers and counters (T, C) − − yes 

Data blocks (DB) − − yes 

Peripheral inputs (PIB, PIW, PID) yes − − 

Peripheral outputs (PQB, PQW, PQD) yes − yes 

Inputs and outputs (I, Q) yes yes yes 

User program can overwrite the 

− yes yes 

modify/force values 

Replacing the force value effective without yes yes − 

interruption 

The variables retain their values when the yes yes − 

application is exited 

The variables retain their values after the 

connection to the CPU is broken 

yes yes − 

Addressing errors permitted: 

e.g. IW1 modify/force value: 1 

IW1 modify/force value: 0 

Setting triggers 

Function only affects variable in visible 

area of active window 

Modify 

− − The last becomes 

effective 

Always trigger 

immediately 

Affects all force 

values 

always trigger 

immediately 

affects all force 

values 

once or every 

cycle 

yes 

Note 

• With "Enable Peripheral Outputs," the force values for forced peripheral outputs 

become effective on the corresponding output modules; the modify values for 

peripheral outputs, however, do not. 

• With forcing, the variable always has the forced value. This value is read during 

each read access to the user program. All forms of write access are ineffective. 

• With permanent modifying, read access to the program is effective and remains 

so until the next trigger point. 


20-22 A5E00706944-01

21 Testing Using Program Status 

You can test your program by displaying the program status (RLO, status bit) or the 

contents of the corresponding registers for every instruction. You can define the 

scope of the information displayed in the "LAD/FBD" tab in the "Customize" dialog 

box. You open this dialog box using the menu command Options > Customize in 

the "LAD/STL/FBD: Programming Blocks" window. 

! 

Warning 

Testing a program while a process is running can lead to serious damage to 

property or persons if errors occur in the function or in the program. 

Ensure that no dangerous situations can occur before you execute this function. 

Requirements 

To display the program status, the following requirements must be fulfilled: 

• You must have saved the block without errors and then downloaded it to the 

CPU. 

• The CPU must be in operation and the user program running. 

Basic Procedure for Monitoring the Program Status 

It is strongly recommended that you do not call the whole program and debug it, 

but call the blocks one by one and debug them individually. You should start with 

the blocks in the last nesting level of the call hierarchy, for example, by calling them 

in OB1 and creating the environment to be tested for the block by monitoring and 

modifying variables. 

 

 

 

 

 

To set breakpoints, and to execute the program in single-step mode, test operation 

mode must be set (see menu command Debug > Operation). These test functions 

are not possible in process operation mode. 


A5E00706944-01 21-1

Testing Using Program Status 

21.1 Program Status Display 

The display of the program status is updated cyclically. It begins with the selected 

network. 

Preset Color Codes in LAD and FBD 

• Status fulfilled: green continuous lines 

• Status not fulfilled: blue dotted lines 

• Status unknown: black continuous lines 

The preset for line type and color can be changed under the menu command 

Options > Customize, "LAD/FBD" tab. 

Status of Elements 

• The status of a contact is: 

- Fulfilled if the address has the value "1," 

- Not fulfilled if the address has the value "0," 

- Unknown if the value of the address is unknown. 

• The status of elements with enable output (ENO) corresponds to the status of a 

contact with the value of the ENO output as the address. 

• The status of elements with a Q output corresponds to the status of a contact 

with the value of the address. 

• The status for CALLs is fulfilled if the BR bit is set following the call. 

• The status of a jump instruction is fulfilled if the jump is executed, meaning if the 

jump condition is fulfilled. 

• Elements with enable output (ENO) are shown in black if the enable output is 

not connected. 

Status of Lines 

• Lines are black if they are not run through or if their status is unknown. 

• The status of lines that start at the power rail is always fulfilled ("1"). 

• The status of lines at the start of parallel branches is always fulfilled ("1"). 

• The status of the line following an element is fulfilled if both the status of the line 

before the element and the status of the element are fulfilled. 

• The status of the line following NOT is fulfilled if the status of the line before 

NOT is not fulfilled (and vice versa). 

• The status of the line after an intersection of a number of lines is fulfilled if: 

- The status of at least one line before the intersection is fulfilled. 

- The status of the line before the branch is fulfilled. 

Status of Parameters 

• The values of parameters in bold type are current. 

• The values of parameters in thin type result from a previous cycle; the program 

section was not processed in the current scan cycle. 


21-2 A5E00706944-01


21.2 What You Should Know About Testing in Single-Step 

Mode/Breakpoints 

When testing in single-step mode you can do the following: 

• Execute programs statement by statement (in single steps) 

• Set breakpoints 

The function "testing in single-step mode" is not possible for all programmable 

controllers (refer to the documentation for the relevant programmable controller). 

Requirements 

• The test operation mode must be set. Testing in single-step mode is not 

possible in process operation mode (see menu command Debug > Operation). 

• Testing in single-step mode is possible only in Statement List. For blocks in 

Ladder Logic or Function Block Diagram you must change the view using the 

menu command View > STL. 

• The block must not be protected. 

• The block must be open online. 

• The opened block must not be changed in the Editor. 


A5E00706944-01 21-3


Number of Breakpoints 

The number of breakpoints is variable and depends on the following: 

• The number of breakpoints already set 

• The number of variable statuses running 

• The number of program statuses running 

Refer to your programmable controller documentation to find out whether it 

supports testing in single-step mode. 

You will find the menu commands you can use to set, activate, or delete 

breakpoints in the "Debug" menu. You can also select these menu commands 

using icons in the breakpoint bar. Display the breakpoint bar using the menu 

command View > Breakpoint Bar. 

Permitted Test Functions 

• Monitor/modify variables 

• Module information 

• Operating mode 

Danger 

Risk of dangerous plant status in HOLD mode. 


21-4 A5E00706944-01


21.3 What You Should Know About the HOLD Mode 

If the program encounters a breakpoint, the programmable controller goes into the 

HOLD operating mode. 

LED Display in HOLD Mode 

• LED RUN flashes 

• LED STOP is lit 

Program Processing in HOLD Mode 

• In HOLD mode, no S7 code is processed, meaning no priority classes are 

processed any further. 

• All timers are frozen: 

- No timer cells are processed 

- All monitoring times are paused 

- The basic clock rate of the time-controlled levels are paused 

• The real time clock continues to run 

• For safety reasons, the outputs are always disabled in HOLD mode ("output 

disable"). 

Behavior following Power Supply Failure in HOLD Mode 

• Programmable controllers with battery backup change to STOP mode and 

remain there following a power supply failure during HOLD mode and a 

subsequent return of power. The CPU does not execute an automatic restart 

(warm restart). From STOP mode you can determine how processing continues 

(for example, by setting/resetting breakpoints, executing a manual restart). 

• Programmable controllers without battery backup are not "retentive" and 

therefore execute an automatic warm restart when power returns, regardless of 

the previous operating mode. 


A5E00706944-01 21-5


21.4 Program Status of Data Blocks 

From STEP 7 version 5 onwards, it is possible to observe a data block online in the 

data view. The display can be activated either by an online data block or by an 

offline data block. In both cases, the contents of the online data block in the 

programmable controller are displayed. 

The data block must not be modified before the program status is started. If there is 

a structural difference (declaration) between the online data block and the offline 

data block, the offline data block can be downloaded to the programmable 

controller directly on request. 

The data block must be located in the "data view," so that the online values can be 

displayed in the "Actual Value" column. Only the part of the data block which is 

visible on the screen is updated. While the status is active, you cannot switch to the 

declaration view. 

While the update is in progress, a green bar is visible in the status bar and the 

operating mode is displayed. 

The values are issued in the format of the respective data type; the format cannot 

be changed. 

After program status has been concluded, the "Actual Value" column displays 

again the contents which were valid before the program status. It is not possible to 

transfer the updated online values to the offline data block. 

Updating data types: 

All the elementary data types are updated in a shared DB, as well as in all the 

declarations (in/out/in-out/stat) of an instance data block. 

Some data types cannot be updated. When the program status is active, fields in 

the "Actual Value" column which contain data which have not been updated are 

displayed with a gray background. 

• The complex data types DATE_AND_TIME and STRING are not updated. 

• In the complex data types ARRAY, STRUCT, UDT, FB, and SFB, only those 

elements which are elementary data types are updated. 

• In the INOUT declaration of an instance data block only the pointer to the 

complex data type is displayed, not the elements of the data type itself. The 

pointer is not updated. 

• Parameter types are not updated 

• Introduction to Monitoring Variables. 


21-6 A5E00706944-01


21.5 Setting the Display for Program Status 

You can set the display of the program status in a Statement List, Function Block 

Diagram, or Ladder Logic block yourself. 

To set the display, proceed as follows: 


2. In the "Customize" dialog box, select the "STL" tab or the "LAD/FBD" tab. 

3. Select the required options for testing the program. You can display the 

following status fields. 

Activate... 

Status bit 

RLO 

...To Display 

Status bit; bit 2 of the status word 

Bit 1 of the status word; 

shows the result of a logic operation or a mathematical comparison 

Standard status Content of accumulator 1 

Address register 

1/2 

Content of the respective address register with register-indirect 

addressing (area-internal or area-crossing) 

Akku2 Content of accumulator 2 

DB register 1/2 Content of the data block register, of the first and/or second open 

data block 

Indirect 

Indirect memory reference; pointer reference (address), not address 

content reference; 

for memory-indirect addressing only, not possible with registerindirect 

addressing. 

Contents of a timer word or counter word if corresponding 

instructions appear in the statement 

Status word All status bits of the status word 


A5E00706944-01 21-7


21.6 Setting the Mode for the Test 

Procedure 

1. Display the set test environment using the menu command Debug > 

Operation. 

2. Select the required mode of operation. You can choose between test operation 

and process operation. 

Mode of 

Operation 

Test operation 

Process 

operation 

Explanation 

All test functions are possible without restriction. 

Significant increases to the CPU scan cycle time can occur because, for example, 

the status of statements in programmed loops is recorded in every cycle. 

The test function program status is restricted to guarantee the minimum possible 

load on the scan cycle time. 

• This means, for example, that no call conditions are permitted. 

• The status display of a programmed loop is aborted at the point of return. 

• The test functions HOLD and single-step program execution are not possible. 

Note 

If the mode of operation was set when you assigned the CPU parameters, you can 

only change the mode by changing the parameters. Otherwise you can change the 

mode in the dialog box displayed. 


21-8 A5E00706944-01

22 Testing using the Simulation Program 

(Optional Package) 

22.1 Testing using the Simulation Program S7-PLCSIM 

(Optional Package) 

With the optional software package PLC Simulation you can run and test your 

program on a simulated programmable controller that exists on your computer or 

programming device (for example, Power PG). As the simulation is realized 

completely by the STEP 7 software, you do not require any S7 hardware (CPU or 

signal modules). Using the simulated S7 CPU you can test and troubleshoot 

programs for S7-300 and S7-400 CPUs. 

This application provides a simple user interface for monitoring and modifying the 

various parameters that are used in your program (for example, for switching inputs 

on and off). You can also use the various applications in the STEP 7 software while 

your program is being processed by the simulated CPU. For example, you can 

monitor and modify variables with the variable table. 


A5E00706944-01 22-1

Testing using the Simulation Program (Optional Package) 


22-2 A5E00706944-01

23 Diagnostics 

23.1 Hardware Diagnostics and Troubleshooting 

You can see whether diagnostic information is available for a module by the 

presence of diagnostics symbols. Diagnostics symbols show the status of the 

corresponding module and, for CPUs, the operating mode as well. 

Diagnostics symbols are displayed in the project window in the online view as well 

as in the quick view (default setting) or the diagnostic view when you call the 

function "Hardware Diagnostics." Detailed diagnostic information is displayed in the 

"Module Information" application, which you can start by double-clicking a 

diagnostics symbol in the quick view or the diagnostic view. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 23-1

Diagnostics 

How to Locate Faults 

1. Open the online window for the project with the menu command View > 

Online. 

2. Open all the stations so that the programmable modules configured in them 

are visible. 

3. Check to see which CPU is displaying a diagnostics symbol indicating an error 

or fault. You can open the help page with an explanation of the diagnostics 

symbols using the F1 key. 

4. Select the station that you want to examine. 

5. Select the menu command PLC > Diagnostics/Settings > Module 

Information… to display the module information for the CPU in this station. 

6. Select the menu command PLC > Diagnostics/Settings > Hardware 

Diagnostics to display the "quick view" with the CPU and the failed modules in 

this station. The display of the quick view is set as default (menu command 

Option > Customize, "View" tab). 

7. Select a faulty module in the quick view. 

8. Click the "Module Information" button to obtain the information on this module. 

9. Click the "Open Station Online" button in the quick view to display the 

diagnostic view. The diagnostic view contains all the modules in the station in 

their slot order. 

10. Double-click a module in the diagnostic view in order to display its module 

information. In this way, you can also obtain information for those modules that 

are not faulty and therefore not displayed in the quick view. 

You do not necessarily have to carry out all of the steps; you can stop as soon as 

you have obtained the diagnostic information you require. 


23-2 A5E00706944-01

Diagnostics 

23.2 Diagnostics Symbols in the Online View 

Diagnostics symbols are displayed in the online project window and in the 

hardware configuration window with the online view of configuration tables. 

Diagnostics symbols make it easier for you to detect a fault. You can see by a 

glance at a module symbol whether diagnostic information is available. If there are 

no faults present, the symbols for the module types are displayed without additional 

diagnostics symbols. 

If diagnostic information is available for a module, a diagnostics symbol is 

displayed in addition to the module symbol or the module symbol is displayed with 

reduced contrast. 

Diagnostics Symbols for Modules (Example: FM / CPU) 

Symbol 

Meaning 

Mismatch between preset and actual 

configuration: the configured module does not 

exist or a different module type is inserted 

Fault: module has a fault. 

Possible causes: diagnostic interrupt, I/O access 

error, or error LED detected 

Diagnosis not possible: no online connection, or 

the CPU does not return diagnostic information to 

the module (for example, power supply, or 

submodule). 

Diagnostics Symbols for Operating Modes (Example: CPU) 

Symbol 

Mode 

STARTUP 

STOP 

STOP 

triggered by STOP mode on another CPU in 

multicomputing operation 

RUN 

HOLD 


A5E00706944-01 23-3

Diagnostics 

Diagnostics Symbol for Forcing 

Symbol 

Mode 

Variables are being forced on this module, 

meaning variables in the user program for the 

module are assigned fixed values that cannot be 

changed by the program. 

The symbol for forcing can also appear in 

combination with other symbols (here with the 

symbol for RUN mode). 

Updating the Display of Diagnostic Symbols 

The appropriate window must be activated. 

• Press F5 or 

• Select the menu command View > Update in the window. 


23-4 A5E00706944-01

Diagnostics 

23.3 Diagnosing Hardware: Quick View 

23.3.1 Calling the Quick View 

The quick view offers you a quick way of using "Diagnosing Hardware" with less 

information than the more detailed displays in the diagnostic view of HW Config. 

The quick view is displayed as default when the "Diagnose Hardware" function is 

called. 

Displaying the Quick View 

You call this function from the SIMATIC Manager using the menu command PLC > 

Diagnostics/Settings > Diagnose Hardware. 

You can use the menu command as follows: 

• In the online window of the project if a module or an S7/M7 program is selected. 

• If a node ("MPI=...") is selected in the "Accessible Nodes" window and this entry 

belongs to a CPU. 

From the configuration tables displayed, you can select modules whose module 

information you want to display. 

23.3.2 Information Functions in the Quick View 

The following information is displayed in the quick view: 

• Data for the online connection to the CPU 

• Diagnostic symbol for the CPU 

• Diagnostic symbols for the modules in which the CPU has detected a fault (for 

example, diagnostic interrupt, I/O access error) 

• Module type and address of the module (rack, slot, DP master system with 

station number). 

Other Diagnostic Options in the Quick View 

• Displaying the Module Information 

You can call this dialog box by clicking the "Module Information" button. The 

dialog box displays detailed diagnostic information, depending on the diagnostic 

capabilities of the selected module. In particular, you can display the entries in 

the diagnostic buffer via the diagnostic information of the CPU. 

• Displaying the Diagnostic View 

Using the "Open Station Online" button, you can open the dialog box which, in 

contrast to the quick view, contains a graphic overview of the whole station as 

well as configuration information. It focuses on the module which is highlighted 

in the list "CPU / Faulty Modules." 


A5E00706944-01 23-5

Diagnostics 

23.4 Diagnosing Hardware: Diagnostic View 

23.4.1 Calling the Diagnostic View 

Using this method you can open the "Module Information" dialog box for all 

modules in the rack. The diagnostic view (configuration table) shows the actual 

structure of a station at the level of the racks and DP stations with their modules. 

Note 

• If the configuration table is already open offline, you can also get the online 

view of the configuration table using the menu command Station > Open 

Online. 

• Depending on the diagnostics capability of the module, a varying number of 

tabs are displayed in the "Module Information" dialog box. 

• In the "Accessible Nodes" window, only the modules with their own node 

address (Ethernet, MPI or PROFIBUS address) are ever visible. 


23-6 A5E00706944-01

Diagnostics 

Calling from the ONLINE view of a project in the SIMATIC Manager 

1. Establish an online connection to the programmable controller using the menu 

command View > Online in the project view in the SIMATIC Manager. 

2. Select a station and open it with a double-click. 

3. Then open the "Hardware" object in it. The diagnostic view is opened. 

Now you can select a module and call up its module information using the menu 

command PLC > Diagnostics/Settings > Module Information. 

Calling from the offline view of a project in the SIMATIC Manager 

Execute the following steps: 

1. Select a station from the project view of the SIMATIC Manager and open it with 

a double-click. 

2. Then open the "Hardware" object in it. The configuration table is opened. 

3. Select the Station > Open Online menu command. 

4. The diagnostic view of HW Config is opened with the station configuration as 

determined from the modules (for example, CPU). The status of the modules is 

indicated by means of symbols. Refer to the online help for the meaning of the 

various symbols. Faulty modules and configured modules which are missing 

are listed in a separate dialog box. From this dialog box you can navigate 

directly to one of the selected module ("Go To" button). 

5. Double-click the symbol for the module whose status you are interested in. A 

dialog box with tabs (depending on the type of module) gives you a detailed 

analysis of the module status. 

Calling from the "Accessible Nodes" window in the SIMATIC Manager 

Execute the following steps: 

1. Open the "Accessible Nodes" window in the SIMATIC Manager using the menu 

command PLC > Display Accessible Nodes. 

2. Select a node in the "Accessible Nodes" window. 

3. Select the menu command PLC > Diagnostics/Settings > Diagnose Hardware. 

Note 

In the "Accessible Nodes" window, only the modules with their own node address 

(Ethernet, MPI or PROFIBUS address) are visible. 


A5E00706944-01 23-7

Diagnostics 

23.4.2 Information Functions in the Diagnostic View 

In contrast to the quick view, the diagnostic view displays the entire station 

configuration available online. This consists of: 

• Rack configurations 

• Diagnostics symbols for all configured modules 

From these, you can read the status of each module and, with CPU modules, 

the operating mode. 

• Module type, order number and address details, comments on the 


Additional Diagnostic Options in the Diagnostic View 

By double-clicking a module, you can display the operating mode of this module. 


23-8 A5E00706944-01

Diagnostics 

23.5 Module Information 

23.5.1 Options for Displaying the Module Information 

You can display the "Module Information" dialog box from different starting points. 

The following procedures are examples of frequently used methods of calling 

module information: 

• In the SIMATIC Manager from a window with the project view "online" or 

"offline." 

• In the SIMATIC Manager from an "Accessible Nodes" window 

• In the diagnostic view of HW Config 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In order to display the status of a module with its own node address, you require 

an online connection to the programmable controller. You establish this connection 

via the online view of a project or via the "Accessible Nodes" window. 


A5E00706944-01 23-9

Diagnostics 

23.5.2 Module Information Functions 

The module information functions can each be found in the various tabs within the 

"Module Information" dialog box. When displayed in an active situation, only those 

tabs relevant to the selected module are displayed. 

Function/Tab Information Use 

General 

Identification data on the selected 

module; for example, order number, 

release number, status, slot in rack 

The online information from the 

inserted module can be compared with 

the data for the configured module 

Diagnostic Buffer 

Diagnostic Interrupt 

DP Slave Diagnostics 

Memory 

Overview of events in the diagnostic 

buffer and detailed information on the 

selected event 

To find the cause of a CPU STOP and 

evaluate the events on the selected 

module leading to it 

Using the diagnostic buffer, errors in 

the system can still be analyzed at a 

later time to find the cause of a STOP 

or to trace back and categorize the 

occurrence of individual diagnostic 

events 

Diagnostic data for the selected module To evaluate the cause of a module fault 

Diagnostic data for the selected DP 

slave (to EN 50170) 

Memory capacity. Current utilization of 

the work memory, load memory and 

retentive memory of the selected CPU 

or M7 function module 

To evaluate the cause of a fault in a DP 

slave 

Before new or extended blocks are 

transferred to a CPU, to check whether 

sufficient load memory is available in 

the CPU/function module or to 

compress the memory content. 

Scan Cycle Time 

Time System 

Performance Data 

Blocks 

(can be opened from 

the "Performance 

Data" tab) 

Communication 

Duration of the longest, shortest, and 

last scan cycle of the selected CPU or 

M7 function module 

Current time, operating hours, and 

information about synchronizing clocks 

(synchronization intervals) 

Address areas and the available blocks 

for the selected module (CPU/FM) 

Display of all block types available in 

the scope of supply of the selected 

module List of OBs, SFBs, and SFCs 

you can use for this module 

Transmission rates, the overview of 

communication connections, the 

communication load, and the maximum 

message frame size on the 

communication bus of the selected 

module 

To keep a check on the configured 

minimum cycle time, and the maximum 

and current cycle times 

To display and set the time and date of 

a module and to check the time 

synchronization 

Before and during the creation of a 

user program to check whether the 

CPU fulfils the requirements for 

executing a user program; for example, 

load memory size or size of the 

process image 

To check which standard blocks your 

user program can contain or call to be 

able to run on the selected CPU. 

To determine how many and which 

CPU or M7 FM connections are 

possible and how many are in use 


23-10 A5E00706944-01

Diagnostics 

Function/Tab Information Use 

Stacks 

Stacks tab: Can only be called up in 

STOP mode or HOLD mode. 

The B stack for the selected module is 

displayed. You can then also display 

the I stack, the L stack, and the nesting 

stack and jump to the error location in 

the interrupted block. 

To determine the cause of a transition 

to STOP and to correct a block 

Additional Information Displayed 

For each tab, the following information is displayed: 

• Online path to the selected module 

• Operating mode of the corresponding CPU (for example, RUN, STOP) 

• Status of the selected module (for example, error, OK) 

• Operating mode of the selected module (for example, RUN, STOP) if it has its 

own operating mode (for example, CP 342-5) 

The operating mode of the CPU itself and the status of the selected module cannot 

be displayed if the module information for a non-CPU module is opened from the 

"Accessible Nodes" window. 

Displaying a Number of Modules Simultaneously 

You can display the module information for a number of modules simultaneously. 

To do this, you must change to the respective module context, select another 

module, and then call the module information for it. Another "Module Information" 

dialog box is then displayed. Only one dialog box can be opened for each module. 

Updating the Display of Module Information 

Each time you switch to a tab in the "Module Information" dialog box, the data are 

read from the module again. While a page is displayed, however, the contents are 

not updated. If you click the "Update" button, you can read the data from the 

module without changing the tab. 


A5E00706944-01 23-11

Diagnostics 

23.5.3 Scope of the Module Type-Dependent Information 

The scope of information that can be evaluated and displayed is dependent on: 

• The module selected, and 

• From which view you call the module information 

A full scope of information is available when called from the online view of the 

configuration tables or from the project window. 

A limited scope of information is available when called from the "Accessible 

Nodes" window. 

Depending on the scope of the information, the modules are divided into the 

categories "with system diagnostic capability," "with diagnostic capability," or 

"without diagnostic capability." The following figure shows these categories: 

 

 

 

 

 

 

 

 

• Modules with system diagnostic capability are, for example, the modules 

FM 351 and FM 354 

• Modules with diagnostic capability are most analog signal modules. 

• Modules without diagnostic capability are most digital signal modules. 

Tabs Displayed 

The table shows which property tabs are present in the "Module Information" dialog 

box for each module type. 

Tab 

CPU or 

M7 FM 

Module with 

System 

Diagnostics 

Capability 


Diagnostics 

Capability 

Module 

without 

Diagnostics 

Capability 

DP Slave 

General yes yes yes yes yes 

Diagnostic Buffer yes yes − − − 

Diagnostic Interrupt − yes yes − yes 

Memory yes − − − − 

Scan Cycle Time yes − − − − 

Time System yes − − − − 

Performance Data yes − − − − 

Stacks yes − − − − 

Communication yes − − − − 


23-12 A5E00706944-01

Diagnostics 

Tab 

CPU or 

M7 FM 


System 

Diagnostics 

Capability 


Diagnostics 

Capability 

Module 

without 

Diagnostics 

Capability 

DP Slave 

DP Slave 

− − − − yes 

Diagnostics 

H state 1) yes − − − − 

1) Only for CPUs in H systems 

In addition to the information in the tabbed property sheets, the operating mode is 

displayed for modules with an operating mode. When you open the dialog box from 

the configuration tables online, the status of the module from the viewpoint of the 

CPU is displayed (for example, OK, fault, module not available). 

23.5.4 Displaying the Module Status of PA Field Devices and DP Slaves 

After a Y-Link 

As of STEP 7 V5.1 Service Pack 3, you can evaluate the module status of DP 

slaves and PA field devices "after" a DP/PA link (IM 157). 

This affects the following configurations: 

• IM 157 with DP/PA connectors for connecting a PROFIBUS-PA 

• IM 157 as a redundant modular interface module for connecting a nonredundant 

PROFIBUS-DP ("Y-link") 

In this configuration, the programming device (PG) is connected to the same 

PROFIBUS subnet as the DP/PA link. 

In addition, there is another configuration option in which the PG is connected to an 

Industrial Ethernet and routes an S7-400 station to the PROFIBUS subnet. 

The prerequisites for this setup are shown in the following diagram: 

IM 157 with DP/PA connectors for connection to PROFIBUS-PA 

 

 

 

 

 

 

 


A5E00706944-01 23-13

Diagnostics 

IM 157 as Y-link 

 

 

 

 

 

 

PG in an Industrial Ethernet 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


23-14 A5E00706944-01

Diagnostics 

23.6 Diagnosing in STOP Mode 

23.6.1 Basic Procedure for Determining the Cause of a STOP 

To determine why the CPU has gone into "STOP" mode, proceed as follows: 

1. Select the CPU that has gone into STOP. 

2. Select the menu command PLC > Diagnostics/Settings > Module 

Information. 

3. Select the "Diagnostic Buffer" tab. 

4. You can determine the cause of the STOP from the last entries in the 

diagnostic buffer. 

If a programming error occurs: 

1. The entry "STOP because programming error OB not loaded" means, for 

example, that the CPU has detected a program error and then attempted to 

start the (non-existent) OB to handle the programming error. The previous 

entry points to the actual programming error. 

2. Select the message relating to the programming error. 

3. Click the "Open Block" button. 

4. Select the "Stacks" tab. 

23.6.2 Stack Contents in STOP Mode 

By evaluating the diagnostic buffer and the stack contents you can determine the 

cause of the fault in the processing of the user program. 

If, for example, the CPU has gone into STOP as a result of a programming error or 

the STOP command, the "Stacks" tab in the module information displays the block 

stack. You can display the contents of the other stacks using the "I Stack", "L 

Stack", and "Nesting Stack" buttons. The stack contents give you information on 

which instruction in which block led to the CPU going into STOP. 

B Stack Contents 

The B stack, or block stack, lists all the blocks that were called before the change 

to STOP mode and which were not completely processed. 


A5E00706944-01 23-15

Diagnostics 

I Stack Contents 

When you click the "I Stack" button, the data at the interrupt location are displayed. 

The I stack, or interrupt stack, contains the data or the states which were valid at 

the time of the interrupt, for example: 

• Accumulator contents and register contents 

• Open data blocks and their size 

• Content of the status word 

• Priority class (nesting level) 

• Interrupted block 

• Block in which program processing continues after the interrupt 

L Stack Contents 

For every block listed in the B stack, you can display the corresponding local data 

by selecting the block and clicking the "L Stack" button. 

The L stack, or local data stack, contains the local data values of the blocks the 

user program was working with at the time of the interrupt. 

In-depth knowledge of the system is required to interpret and evaluate the local 

data displayed. The first part of the data displayed corresponds to the temporary 

variables for the block. 

Nesting Stack Contents 

When you click the "Nesting Stack" button, the contents of the nesting stack at the 

interrupt location are displayed. 

The nesting stack is a memory area that the logic operations A(, AN(, O(, ON(, X(, 

and XN( use. 

The button is only active if bracket expressions were still open at the time of 

interruption. 


23-16 A5E00706944-01

Diagnostics 

23.7 Checking Scan Cycle Times to Avoid Time Errors 

The "Scan Cycle Time" tab in the module information gives information about the 

scan cycle times of the user program. 

If the duration of the longest cycle time is close to the configured maximum scan 

cycle time, there is a danger that fluctuations in the cycle time might cause a time 

error. This can be avoided if you extend the maximum cycle time (watchdog time) 

of the user program. 

If the cycle length is less than the configured minimum scan time, the cycle is 

automatically extended by the CPU/FM to the configured minimum cycle time. In 

the case of a CPU, the background OB (OB90) is processed during this extended 

time (if it has been downloaded). 

Setting the Scan Cycle Time 

You can set the maximum and minimum cycle times when you configure the 

hardware. To do this, double-click in the offline view of the configuration table on 

the CPU/FM to define its properties. You can enter the appropriate values in the 

"Cycle/Clock Memory" tab. 


A5E00706944-01 23-17

Diagnostics 

23.8 Flow of Diagnostic Information 

The following figure shows the flow of diagnostic information in SIMATIC S7. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Displaying Diagnostic Information 

You can read out the diagnostic entries using SFC51 RDSYSST in the user 

program or display the diagnostic messages in plain language with STEP 7. 

They provide information about the following: 

• Where and when the error occurred 

• The type of diagnostic event to which the entry belongs (user-defined diagnostic 

event, synchronous/asynchronous error, operating mode change). 


23-18 A5E00706944-01

Diagnostics 

Generating Process Control Group Messages 

The CPU enters events of the standard diagnostics and extended diagnostics in 

the diagnostic buffer. It also generates a process control group message for the 

standard diagnostic events if the following conditions are met: 

• You have specified that process control messages will be generated in STEP 7. 

• At least one display unit has logged on at the CPU for process control 

messages. 

• A process control group message is only generated when there is not currently 

a process control group message of the corresponding class (there are seven 

classes). 

• One process control group message can be generated per class. 

23.8.1 System Status List SSL 

The system status list (SSL) describes the current status of the programmable logic 

controller. It provides an overview of the configuration, the current parameter 

assignment, the current statuses and sequences on the CPU, and the modules 

belonging to it. 

You can only read the data in the system status list but not modify them. It is a 

virtual list that is only created on request. 

The information that you can display using the system status list can be divided 

into four areas. 

 

 

 

 

 

 

 

Reading Out the System Status List 

There are two ways of reading out the information in system status lists, as follows: 


A5E00706944-01 23-19

Diagnostics 

• Implicitly, via STEP 7 menu commands from the programming device (for 

example, memory configuration, static CPU data, diagnostic buffer, status 

displays). 

• Explicitly, via the system function SFC 51 RDSYSST in the user program, by 

entering the number of the required partial system status list (see Help on 

Blocks ) 

System Data of the System Status List 

System data are intrinsic or assigned characteristic data of a CPU. The following 

table shows the topics about which information can be displayed (partial system 

status lists): 

Topic 

Module identification 

CPU characteristics 

Memory areas 

System areas 

Block types 

Assignment of interrupts and 

errors 

Interrupt status 

Status of the priority classes 

Operating mode and mode 

transition 

Information 

Order number, type ID, and version of the module 

Time system, system behavior (for example,. 

multicomputing) and language description of the CPU 

Memory configuration of the module (size of the work 

memory). 

System memory of the module (for example, number 

of memory bits, timers, counters, memory type). 

Which blocks (OB, DB, SDB, FC, FB) exist on the 

module, the maximum number of blocks of one type, 

and the maximum size of a block type 

Assignment of interrupts/errors to OBs 

Current status of interrupt processing/interrupts 

generated 

Which OB is being executed, which priority class is 

disabled due to the parameter setting 

Which operating modes are possible, the last 

operating mode change, the current operating mode 


23-20 A5E00706944-01

Diagnostics 

Diagnostic Status Data in the CPU 

Diagnostic status data describe the current status of the components monitored by 

the system diagnostics. The following table shows the topics about which 

information can be displayed (partial system status lists): 

Topic 

Communication status data 

Diagnostic modules 

Start information list of the OB 

Start event list 

Module status information 

Information 

All the communication functions currently set in the system 

The modules with diagnostics capability logged on at the CPU 

Start information about the OBs of the CPU 

Start events and priority classes of the OBs 

Status information about all assigned modules that are plugged in, 

faulty, or generate hardware interrupts 

Diagnostic Data on Modules 

In addition to the CPU, there are also other modules with diagnostic capabilities 

(SMs, CPs, FMs) whose data are entered in the system status list. The following 

table shows the topics about which information can be displayed (partial system 

status list): 

Topic 

Module diagnostic information 

Module diagnostic data 

Information 

Module start address, internal/external faults, channel faults, 

parameter errors (4 bytes) 

All the diagnostic data of a particular module 


A5E00706944-01 23-21

Diagnostics 

23.8.2 Sending Your Own Diagnostic Messages 

You can also extend the standard system diagnostics of SIMATIC S7 by using the 

system function SFC 52 WRUSMSG to: 

• Enter your own diagnostic information in the diagnostic buffer (for example, 

information about the execution of the user program). 

• Send user defined diagnostic messages to logged on stations (monitoring 

devices such as a PG, OP or TD). 

User Defined Diagnostic Events 

The diagnostic events are divided into event classes 1 to F. The user defined 

diagnostic events belong to event classes 8 to B. These can be divided into two 

groups, as follows: 

• Event classes 8 and 9 include messages with a fixed number and predefined 

text that you can call up based on the number. 

• Event classes A and B include messages to which you can assign a number 

(A000 to A0FF, B000 to B0FF) and text of your own choice. 

Sending Diagnostic Messages to Stations 

In addition to making a user defined entry in the diagnostic buffer, you can also 

send your own user defined diagnostic messages to logged on display devices 

using SFC52 WRUSMSG. When SFC52 is called with SEND = 1, the diagnostic 

message is written to the send buffer and automatically sent to the station or 

stations logged on at the CPU. 

If it is not possible to send messages (for example, because no display device is 

logged on or because the send buffer is full) the user-defined diagnostic event is 

still entered in the diagnostic buffer. 

Generating a Message with Acknowledgement 

If you acknowledge a user defined diagnostic event and want to record the 

acknowledgement, proceed as follows: 

• When the event enters the event state, write 1 to a variable of the type BOOL, 

when the event leaves the event state write 0 to the variable. 

• You can then monitor this variable using SFB33 ALARM. 


23-22 A5E00706944-01

Diagnostics 

23.8.3 Diagnostic Functions 

System diagnostics detect, evaluate, and report errors that occur within a 

programmable controller. For this purpose, every CPU and every module with 

system diagnostics capability (for example, FM 354) has a diagnostic buffer in 

which detailed information on all diagnostic events is entered in the order they 

occurred. 

Diagnostic Events 

The following entries are displayed as diagnostic events, for example: 

• Internal and external faults on a module 

• System errors in the CPU 

• Operating mode changes (for example, from RUN to STOP) 

• Errors in the user program 

• Inserting/removing modules 

• User messages entered with the system function SFC52 

The content of the diagnostic buffer is retained following a memory reset. Using the 

diagnostic buffer, errors in the system can still be analyzed at a later time to find 

the cause of a STOP or to trace back and categorize the occurrence of individual 

diagnostic events 

Acquiring Diagnostic Data 

You do not need to program the acquisition of diagnostic data by system 

diagnostics. This is a standard feature that runs automatically. SIMATIC S7 

provides various diagnostic functions. Some of these functions are integrated on 

the CPU, others are provided by the modules (SMs, CPs, and FMs). 

Displaying Faults 

Internal and external module faults are displayed on the front panels of the module. 

The LED displays and their evaluation are described in the S7 hardware manuals. 

With the S7-300, internal and external faults are displayed together as a group 

error. 

The CPU recognizes system errors and errors in the user program and enters 

diagnostic messages in the system status list and the diagnostic buffer. These 

diagnostic messages can be read out on the programming device. 

Signal and function modules with diagnostic capability detect internal and external 

module errors and generate a diagnostic interrupt to which you can react using an 

interrupt OB. 


A5E00706944-01 23-23

Diagnostics 

23.9 Program Measures for Handling Errors 

When it detects errors in program processing (synchronous errors) and errors in 

the programmable controller (asynchronous errors), the CPU calls the appropriate 

organization block (OB) for the error: 

Error 

I/O redundancy error 

CPU redundancy error 

Time error 

Power supply error 

Diagnostic interrupt 

Insert/remove module interrupt 

CPU hardware fault 

Priority class error 

Rack failure or failure of a station in the distributed I/O 

Communication error 

Programming error 

I/O access error 

Error OB 

OB70 

OB72 

OB80 

OB81 

OB82 

OB83 

OB84 

OB85 

OB86 

OB87 

OB121 

OB122 

If the appropriate OB is not available, the CPU goes into STOP mode (exceptions: 

OB70, OB72, OB81, OB87). Otherwise, it is possible to store instructions in the OB 

as to how it should react to this error situation. This means the effects of an error 

can be reduced or eradicated. 


Creating and Opening the OB 

1. Display the module information for your CPU. 

2. Select the "Performance Data" tab. 

3. Decide on the basis of the list displayed whether the OB you want to program 

is permitted for this CPU. 

4. Insert the OB in the "Blocks" folder of your program and open the OB. 

5. Enter the program for handling the error. 

6. Download the OB to the programmable controller. 


23-24 A5E00706944-01

Diagnostics 

Programming Measures for Handling Errors 

1. Evaluate the local data of the OB to determine the exact cause of the error. 

The variables OB8xFLTID and OB12xSWFLT in the local data contain the error 

code. Their meaning is described in the "System and Standard Functions 

Reference Manual." 

2. Branch to the program segment which reacts to this error. 

You will find an example of handling diagnostic interrupts in the reference online 

help on System and Standard Functions under the heading "Example of Module 

Diagnostics with SFC51 (RDSYSST)." 

You can find detailed information on OBs, SFBs, and SFCs in the corresponding 

Help on Blocks. 

23.9.1 Evaluating the Output Parameter RET_VAL 

Using the RET_VAL output parameter (return value), a system function indicates 

whether or not the CPU was able to execute the SFC function correctly 

Error Information in the Return Value 

The return value is of the integer data type (INT). The sign of an integer indicates 

whether it is a positive or negative integer. The relationship of the return value to 

the value "0" indicates whether or not an error occurred while the function was 

being executed (see table): 

• If an error occurs while the function is being executed, the return value is less 

than "0." The sign bit of the integer is "1." 

• If the function is executed free of errors, the return value is greater than or equal 

to "0." The sign bit of the integer is "0." 

Processing of the SFC by the CPU Return Value Sign of the Integer 

Error occurred Less than "0" Negative (sign bit is "1") 

No error 

Greater than or Positive (sign bit is "0") 

equal to "0" 


A5E00706944-01 23-25

Diagnostics 

Reacting to Error Information 

If an error occurs while an SFC is being executed, the SFC provides an error code 

in the return value (RET_VAL). 

A distinction is made between the following: 

• A general error code that all SFCs can output and 

• A specific error code that the SFC can output depending on its specific function. 

Transferring the Function Value 

Some SFCs also use the output parameter RET_VAL to transfer the function value, 

for example, SFC64 TIMETCK transfers the system time it has read using 

RET_VAL. 

You can find more detailed information on the output parameter RET_VAL in the 

Help on SFBs/SFCs. 

23.9.2 Error OBs as a Reaction to Detected Errors 

Detectable Errors 

The system program can detect the following errors: 

• CPU functioning incorrectly 

• Error in the system program execution 


• Error in the I/Os 

Depending on the type of error, the CPU is set to STOP mode or an error OB is 

called. 

Programming Reactions 

You can design programs to react to the various types of errors and to determine 

the way in which the CPU reacts. The program for a particular error can then be 

saved in an error OB. If the error OB is called, the program is executed. 

 

 

 

 

 

 


23-26 A5E00706944-01

Diagnostics 

Error OBs 

A distinction is made between synchronous and asynchronous errors as follows: 

• Synchronous errors can be assigned to an MC7 instruction (for example, load 

instruction for a signal module which has been removed). 

• Asynchronous errors can be assigned to a priority class or to the entire 

programmable logic controller (for example, cycle time exceeded). 

The following table shows what types of errors can occur. Refer to your "S7-300 

Programmable Controller, Hardware and Installation Manual" or the "S7-400, 

M7-400 Programmable Controllers, Hardware and Installation Manual" for 

information as to whether your CPU provides the specified OBs. 

Error Class Error Type OB Priority 

Redundancy I/O redundancy error (only 

in H CPUs) 

OB 70 25 

CPU redundancy error OB 72 28 

(only in H CPUs) 

Asynchronous Time error OB 80 26 

Power supply error OB 81 (or 28 if the error OB is called 

Diagnostic Interrupt OB 82 in the startup program) 

Insert/remove module OB 83 

interrupt 

CPU hardware fault OB 84 

Program sequence error OB 85 

Rack failure OB 86 

Communication error OB 87 

Synchronous Programming error OB 121 Priority of the OB that caused 

the error 

I/O access error OB 122 


A5E00706944-01 23-27

Diagnostics 

Example of Using Error OB81 

Using the local data (start information) of the error OB, you can evaluate the type of 

error that has occurred. 

If, for example, the CPU detects a battery error, the operating system calls OB81 

(see figure). 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

You can write a program that evaluates the event code triggered by the OB81 call. 

You can also write a program that brings about a reaction, such as activating an 

output connected to a lamp on the operator station. 


23-28 A5E00706944-01

Diagnostics 

Local Data of Error OB81 

The following table shows the temporary variables that must be declared, in this 

case, in the variable declaration table of OB81. 

The symbol Battery error (BOOL) must be identified as an output (for example, 

Q 4.0) so that other parts of the program can access these data. 

Decl. Name Type Description 

TEMP OB81EVCLASS BYTE Error class/error identifier 39xx 

TEMP OB81FLTID BYTE Error code: 

b#16#21 = 

At least one backup battery of the CPU is 

exhausted 1) 

b#16#22 = 

No backup voltage in the CPU 

b#16#23 = 

Failure of the 24-V power supply in 

the CPU 1 

b#16#31 = 

At least one backup battery of an expansion 

rack is exhausted 1) 

b#16#32 = 

Backup voltage not present in an expansion 

rack 1 

b#16#33 = 

Failure of the 24-V power supply of an 

expansion rack 1) 

TEMP OB81PRIORITY BYTE Priority class = 26/28 

TEMP OB81OBNUMBR BYTE 81 = OB81 

TEMP OB81RESERVED1 BYTE Reserved 

TEMP OB81RESERVED2 BYTE Reserved 

TEMP OB81MDLADDR INT Reserved 

TEMP OB81RESERVED3 BYTE Only relevant for error codes B#16#31, 

B#16#32, B#16#33 

TEMP OB81RESERVED4 BYTE 



TEMP OB81DATETIME DATEAND Date and time at which the OB was started 

TIME 

1) = Not with the S7-300. 


A5E00706944-01 23-29

Diagnostics 

Sample Program for the Error OB81 

The sample STL program shows how you can read the error code in OB81. 

The program is structured as follows: 

• The error code in OB81 (OB81FLTID) is read and compared with the value of 

the event "battery exhausted" (B#16#3921). 

• If the error code corresponds to the code for "battery exhausted," the program 

jumps to the label Berr and activates the output batteryerror. 

• If the error code does not correspond to the code for "battery exhausted," the 

program compares the code with the code for "battery failure". 

• If the error code corresponds to the code for "battery failure," the program jumps 

to the label Berr and activates the output batteryerror. Otherwise the block is 

terminated. 

AWL 

Description 

L B#16#21 // Compare event code "battery exhausted" 

//(B#16#21) with 

L #OB81_FLT_ID // the error code for OB81. 

==I 

// If the same (battery is exhausted), 

// jump to Berr. 

JC Berr 

L B#16#22 // Compare event code "battery failure" 

// (b#16#22) with 

==I 

// the error code for OB81. 

JC BF 

// If the same, jump to Berr. 

BEU 

// No message about battery failure 

Berr: L B#16#39 // Compare the ID for the next event with 

L #OB81_EV_CLASS // the error code for OB81. 

==I 

// If a battery failure or an exhausted battery 

// is found, 

S batteryerror // set the output "battery error." 

// (Variable from the symbol table) 

L B#16#38 // Compare the ID for the concluding event with 

==I 

// the error code for OB81. 

R batteryerror // reset the output "battery error, when 

// the error is fixed. 

You can find detailed information on OBs, SFBs, and SFCs, as well as an 

explanation of event IDs, in the corresponding Help on Blocks. 


23-30 A5E00706944-01

Diagnostics 

23.9.3 Inserting Substitute Values for Error Detection 

With certain types of error (for example, a wire break affecting an input signal), you 

can supply substitute values for values that are not available due to the error. 

There are two ways in which you can supply substitute values: 

• You can assign substitute values for configurable output modules using 

STEP 7. Output modules that cannot have parameters assigned have the 

default substitute value 0. 

• Using SFC44 RPLVAL, you can program substitute values in error OBs (only for 

input modules). 

For all load instructions that lead to synchronous errors, you can specify a 

substitute value for the accumulator content in the error OB. 

Sample Program for Substituting a Value 

In the following sample program, a substitute value is made available in SFC44 

RPLVAL. The following figure shows how OB122 is called when the CPU 

recognizes that an input module is not reacting. 

 

 

 

 

 

 

In this example, the substitute value in the following figure is entered in the 

program so that the program can continue to operate with feasible values. 

 

 

 

 

 

If an input module fails, the processing of the statement L PIB0 produces a 

synchronous error and starts OB122. As standard, the load instruction reads in the 

value 0. With SFC44, however, you can define any substitute value suitable for the 

process. The SFC replaces the accumulator content with the specified substitute 

value. 

The following sample program could be written in OB122. The following table 

shows the temporary variables that must be declared, in this case, in the variable 

declaration table of OB122. 


A5E00706944-01 23-31

Diagnostics 

Decl. Name Type Description 

TEMP OB122EVCLASS BYTE Error class/error ID 29xx 

TEMP OB122SWFLT BYTE Error code: 

16#42, 16#43, 16#44 1) , 16#45 1) 

TEMP OB122PRIORITY BYTE Priority class = priority of the OB in which the 

error occurred 

TEMP OB122OBNUMBR BYTE 122 = OB122 

TEMP OB122BLKTYPE BYTE Block type in which the error occurred 

TEMP OB122MEMAREA BYTE Memory area and type of access 

TEMP OB122MEMADDR WORD Address in the memory at which the error 

occurred 

TEMP OB122BLKNUM WORD Number of the block in which the error occurred 

TEMP OB122PRGADDR WORD Relative address of the instruction that caused 

the error 

TEMP OB122DATETIME DATEANDTIME Date and time at which the OB was started 

TEMP Error INT Saves the error code of SFC44 

1) 

Not with the S7-300. 

STL 

Aerr: 

Stop: 

L B#16#2942 

L #OB122SWFLT 

==I 

JC Aerr 

L B#16#2943 

I 

JC Stop 

CALL "REPL_VAL" 

VAL : = DW#16#2912 

RETVAL : = #Error 

L #Error 

L 0 

==I 

BEC 

CALL "STP" 

Description 

Compare the event code of OB122 with the 

event code (B#16#2942) for the 

acknowledgement of a time error when 

reading the I/O. If the same, jump to 

"Aerr". 

Compare the event code of OB122 with the 

event code (B#16#2943) for an addressing 

error (writing to a module that does not 

exist). If not the same, jump to "Stop." 

Label "Aerr": transfers DW#16#2912 (binary 

10010) to SFC44 (REPL_VAL). SFC44 loads 

this value in accumulator 1 (and 

substitutes the value that triggered the 

OB122 call). The SFC error code is saved in 

#Error. 

Compare #Error with 0 (if the same, no 

error occurred when executing OB122). End 

the block if no error occurred. 

"Stop" label: calls SFC46 "STP" and changes 

the CPU to STOP mode. 


23-32 A5E00706944-01

Diagnostics 

23.9.4 I/O Redundancy Error (OB70) 

Description 

The operating system of a H CPU calls OB70 if a loss of redundancy occurs on the 

PROFIBUS DP (for example, if there is a bus failure on the active DP master or an 

error in the DP slave interface module) or if the active DP master changes from DP 

slaves with switched I/Os. 


You must create OB70 as an object in your S7 program using STEP 7. Write the 

program to be executed in OB70 in the generated block and download it to the 

CPU as part of your user program. 

You can use OB70, for example, for the following purposes: 

• To evaluate the start information of OB70 and determine which event triggered 

the loss of I/O redundancy. 

• To determine the status of your system using SFC51 RDSYSST 

(SZLID=B#16#71). 

The CPU does not change to STOP mode if an I/O redundancy error occurs and 

OB70 is not programmed. 

If OB70 is downloaded and the H system is not in redundant mode, OB70 is 

processed in both CPUs. The H system remains in redundant mode. 




A5E00706944-01 23-33

Diagnostics 

23.9.5 CPU Redundancy Error (OB72) 

Description 

The operating system of the H CPU calls OB72 if one of the following events 

occurs: 

• Loss of redundancy on the CPUs 

• Comparison error (for example, RAM, PIQ) 

• Standby-master switchover 

• Synchronization error 

• Error in a SYNC submodule 

• Update process aborted 

• OB72 is executed by all CPUs which are in RUN mode or STARTUP mode after 

an accompanying start event. 






• To evaluate the start information of OB72 and determine which event triggered 

the loss of CPU redundancy. 

• To determine the status of your system using SFC51 RDSYSST 

(SZLID=B#16#71). 

• To react to the loss of CPU redundancy specifically for the plant. 

The CPU does not change to STOP mode if a CPU redundancy error occurs and 

OB72 is not programmed. 




23-34 A5E00706944-01

Diagnostics 

23.9.6 Time Error (OB80) 

Description 

The operating system of the CPU calls OB80 when a time error occurs. Time errors 

include the following, for example: 

• Maximum cycle time exceeded 

• Time-of-day interrupts skipped by moving the time forward 

• Delay too great when processing a priority class 






• To evaluate the start information of OB80 and to determine which time-of-day 

interrupts were skipped. 

• By including SFC29 CANTINT, you can deactivate the skipped time-of-day 

interrupt so that it is not executed and only time-of-day interrupts relative to the 

new time will be executed. 

If you do not deactivate skipped time-of-day interrupts in OB80, the first skipped 

time-of-day interrupt is executed, all others are ignored. 

If you do not program OB80, the CPU changes to STOP mode when a time error is 

detected. 




A5E00706944-01 23-35

Diagnostics 

23.9.7 Power Supply Error (OB81) 

Description 

The operating system of the CPU calls OB81 if one of the following fails in a CPU 

or an expansion unit 

• The 24-V voltage supply 

• A battery 

• The complete backup 

This OB is also called when the problem has been eliminated (the OB is called 

when an event comes and goes). 





You can, for example, use OB81 for the following purposes: 

• To evaluate the start information of OB81 and determine which power supply 

error has occurred. 

• To find out the number of the rack with the defective power supply. 

• To activate a lamp on an operator station to indicate that maintenance 

personnel should replace a battery. 

If you do not program OB81, the CPU does not change to STOP mode if a power 

supply error is detected. The error is, however, entered in the diagnostic buffer and 

the corresponding LED on the front panel indicates the error. 




23-36 A5E00706944-01

Diagnostics 

23.9.8 Diagnostic Interrupt (OB82) 

Description 

The operating system of the CPU calls OB82 when a module with diagnostics 

capability on which you have enabled the diagnostic interrupt detects an error and 

when the error is eliminated (the OB is called when the event comes and goes). 





You can, for example, use OB82 for the following purposes: 

• To evaluate the start information of OB82. 

• To obtain exact diagnostic information about the error that has occurred. 

When a diagnostic interrupt is triggered, the module on which the problem has 

occurred automatically enters 4 bytes of diagnostic data and their start address in 

the start information of the diagnostic interrupt OB and in the diagnostic buffer. This 

provides you with information about when an error occurred and on which module. 

With a suitable program in OB82, you can evaluate further diagnostic data for the 

module (which channel the error occurred on, which error has occurred). Using 

SFC51 RDSYSST, you can read out the module diagnostic data and enter this 

information in the diagnostic buffer with SFC52 WRUSRMSG. You can also send a 

user-defined diagnostic message to a monitoring device. 

If you do not program OB82, the CPU changes to STOP mode when a diagnostic 

interrupt is triggered. 




A5E00706944-01 23-37

Diagnostics 

23.9.9 Insert/Remove Module Interrupt (OB83) 

Description 

S7-400 CPUs monitor the presence of modules in the central rack and expansion 

racks at intervals of approximately 1 second. 

After the power supply is turned on, the CPU checks whether all the modules listed 

in the configuration table created with STEP 7 are actually inserted. If all the 

modules are present, the actual configuration is saved and is used as a reference 

value for cyclic monitoring of the modules. In each scan cycle, the newly detected 

actual configuration is compared with the previous actual configuration. If there are 

discrepancies between the configurations, an insert/remove module interrupt is 

signaled and an entry is made in the diagnostic buffer and the system status list. In 

RUN mode, the insert/remove module interrupt OB is started. 

Note 

Power supply modules, CPUs, and IMs must not be removed in RUN mode. 

Between removing and inserting a module, at least two seconds must be allowed to pass so 

that the CPU can detect that a module has been removed or inserted. 

Assigning Parameters to a Newly Inserted Module 

If a module is inserted in RUN mode, the CPU checks whether the module type of 

the new module matches the original module. If they match, the module is 

assigned parameters. Either the default parameters or the parameters you 

assigned with STEP 7 are transferred to the module. 







• By including system functions SFC55 to 59, to assign parameters to a newly 

inserted module. 

If you do not program OB83, the CPU changes from RUN to STOP when an 

insert/remove module interrupt occurs. 




23-38 A5E00706944-01

Diagnostics 

23.9.10 CPU Hardware Fault (OB84) 

Description 

The operating system of the CPU calls OB84 when an error is detected on the 

interface to the MPI network, to the communication bus, or to the network card for 

the distributed I/Os; for example, if an incorrect signal level is detected on the line. 

The OB is also called when the error is eliminated (the OB is called when the event 

comes and goes). 







• By including system function SFC52 WRUSMSG to send a message to the 

diagnostic buffer. 

If you do not program OB84, the CPU changes to STOP mode when a CPU 

hardware fault is detected. 




A5E00706944-01 23-39

Diagnostics 

23.9.11 Program Sequence Error (OB85) 

Description 

The operating system of the CPU calls OB85: 

• When a start event for an interrupt OB exists but the OB cannot be executed 

because it has not been downloaded to the CPU. 

• When an error occurs accessing the instance data block of a system function 

block. 

• When an error occurs updating the process image table (module does not exist 

or defective). 






• To evaluate the start information of OB85 and determine which module is 

defective or not inserted (the module start address is specified). 

• By including SFC49 LGCGADR to find out the slot of the module involved. 

If you do not program OB85, the CPU changes to STOP mode when a priority 

class error is detected. 




23-40 A5E00706944-01

Diagnostics 

23.9.12 Rack Failure (OB86) 

Description 

The operating system of the CPU calls OB86 when it has detected one of the 

following events: 

• Failure of a central expansion rack (not for S7-300) such as a broken 

connecting line, distributed power failure on a rack 

• Failure of a master system or a slave (PROFIBUS DP) or failure of an IO 

system or an IO device (PROFINET IO) 

OB86 is also called when the error is eliminated (the OB is called when the event 

comes and goes). 






• To evaluate the start information of OB86 and determine which rack is defective 

or missing. 

• To enter a message in the diagnostic buffer with system function SFC 52 

WRUSMSG and to send the message to a monitoring device. 

If you do not program OB86, the CPU changes to STOP mode when a rack failure 

is detected. 




A5E00706944-01 23-41

Diagnostics 

23.9.13 Communication Error (OB87) 

Description 

The operating system of the CPU calls OB87 when a communication error occurs 

in data exchange using communication function blocks or in global data 

communication, for example: 

• When receiving global data, an incorrect frame ID was detected 

• The data block for the status information of the global data does not exist or is 

too short. 







• To create a data block if the data block for the status information of global data 

communication is missing. 

The CPU does not change to "STOP" mode when a communication error is 

detected and OB87 is not programmed. 




23-42 A5E00706944-01

Diagnostics 

23.9.14 Programming Error (OB121) 

Description 

The operating system of the CPU calls OB121 when a programming error occurs, 

for example: 

• Addressed timers do not exist. 

• A called block is not loaded. 







• To enter the cause of an error in a message data block. 

If you do not program OB121, the CPU changes to STOP mode when a 

programming error is detected. 




A5E00706944-01 23-43

Diagnostics 

23.9.15 I/O Access Error (OB122) 

Description 

The operating system of the CPU calls OB122 when a STEP 7 instruction 

accesses an input or output of a signal module to which no module was assigned 

at the last warm restart, for example: 

• Errors with direct I/O access (module defective or missing) 

• Access to an I/O address that is not known to the CPU. 






• To evaluate the start information of OB122 

• To call the system function SFC 44 and supply a substitute value for an input 

module so that program execution can continue with a meaningful, processdependent 

value. 

If you do not program OB122, the CPU changes to STOP mode when an I/O 

access error is detected. 




23-44 A5E00706944-01

24 Printing and Archiving 

24.1 Printing Project Documentation 

Once you have finished creating the program for your automation task, you can 

print out all the important data for project documentation purposes using the print 

functions integrated in STEP 7. 

Parts of the Project You Can Print 

You can print the contents of objects both directly from the SIMATIC Manager and 

by opening the respective object and starting the print procedure. 

The following parts of a project can be printed directly via the SIMATIC Manager: 

• Object tree (structure of the project/library) 

• Object lists (contents of an object folder) 

• Object contents 

• Messages 

By opening the respective object, the following parts of a project can be printed: 

• Blocks in Ladder Logic, Statement List, or Function Block Diagram 

representation or in other languages (optional software) 

• Symbol table with the symbolic names for absolute addresses 

• Configuration table with the arrangement of modules in the programmable 

controller and the module parameters 

• Diagnostic buffer content 

• Variable table with monitor formats, and monitor and modify values 

• Reference data; such as cross-reference lists, assignment lists, program 

structures, lists of unused addresses, lists of addresses without symbols 

• Global data table 

• Module information with the module status 

• Operator related texts (user texts and text libraries) 

• Documents from optional packages such as other programming languages 

DOCPRO Optional Package 

To create, edit, and print standardized wiring manuals you can use the optional 

software package DOCPRO. This creates plant documentation that fulfils the DIN 

and ANSI standards. 


A5E00706944-01 24-1

Printing and Archiving 

24.1.1 Basic Procedure when Printing 

To print, proceed as follows: 

1. Open the appropriate object to display the information you want to print on the 

screen. 

2. Open the "Print" dialog box using the menu command File > Print in the 

application window. Depending on which application you are in, the first entry 

in the menu bar may not be "File", but the object processed by the application, 

such as "Symbol Table." 

3. If necessary, change the print options (printer, print range, number of copies 

etc.) in the dialog box and close it. 

Some dialog boxes have a "Print" button, for example, the "Module Information" 

dialog box. Click this button to print the contents of the dialog box. 

Blocks do not need to be opened. You can print them directly in the SIMATIC 

Manager using the menu command File > Print. 

24.1.2 Print Functions 

The following additional functions are available for printing print objects: 

Print Objects Menu Command Function Function Function 

Print preview Page setup, 

"Paper format" tab 

Page setup, 

"Headers and 

Footers" tab 

Blocks, STL source File > * • • • 

files 

Module information − • • 

Global data table GD Table> * • • • 

Configuration table Station > * • • • 

Object, object folder File > * − • • 

Reference data Reference Data > * • • • 

Symbol table Table > * • • • 

Variable table Table > * − • • 

Connection table Network > * • • • 

Operator related Texts > * • • • 

texts (user texts, text 

libraries) 

* : The * symbol serves as a wildcard for the respective function in the menu command (e.g. print 

preview or page setup) 

Step-for-step instructions for printing the individual print objects can be found 

under: 

How to Print. 


24-2 A5E00706944-01


Print Preview 

You can use the "Print Preview" function to display the page layout of the 

document to be printed. 

Note 

The print format of the finished document is not displayed in the print preview. 

Setting the Page Format and the Headers and Footers 

You can set the paper size (such as A4, A5, Letter) and the page format and the 

orientation (portrait or landscape) for all documents that you want to print with the 

File > Page Setup menu command. In addition, you can select whether the 

settings should apply to the entire project only for the current session. 

Adjust the layout of the document so that it matches the required paper format. If 

the document is too wide, the right-hand margin will be printed on a consecutive 

page. 

If you select a page format with a margin (for example, A4 margin), the printed 

document has a margin on the left of the page that you can use to punch holes for 

binding. 

To set headers and footers for the documents you want to print throughout the 

project or only for the current session, go to the "Labeling Fields" tab. 

24.1.3 Special Note on Printing the Object Tree 

In the "Print Object List" dialog box, in addition to the object list you can also print 

the object tree by selecting the option "Tree window." 

If you select the option "All" under "Print range," the whole tree structure is printed. 

If you select the option button "Selection," the tree structure from the selected 

object downwards is printed. 

Note 

The settings made in the dialog box apply only to printing the list or tree and not for 

printing the contents of the objects; the settings in the relevant applications are 

used for this. 


A5E00706944-01 24-3


24.2 Archiving Projects and Libraries 

You can store individual projects or libraries in compressed form in an archive file. 

This compressed storage procedure is possible on a hard disk or on a portable 

data medium (such as a floppy disk). 

Archive Programs 

In STEP 7, you can use the archive program of your choice. The archiving 

programs ARJ and PKZIP 4.0 are included as a part of the STEP 7 package. 

These programs and their descriptions are located in the installation path in the 

folder ...\Step7\S7bin\. 

You will require the following versions if you use one of the archive programs below 

(or a newer version): 

• PKZip Commandline V4.0 (included with STEP 7) 

• WinZip from version 6.0 

• JAR from version 1.02 

• ARJ V2.4.1a (only for retrieving archives, included with STEP 7) 

• ARJ32 V3.x (only for retrieving archives) 

• LHArc from version 2.13 (only for retrieving archives) 

Special Issues 

As of STEP 7 V5.2, only the archiving programs PKZip 4.0, JAR, WinZip are 

supported. However, the other programs listed above are supported for retrieval. 

If, in earlier versions of STEP 7, the program ARJ32 V3.x was used to create 

archives, then these archives can only be retrieved with this same program. 

Creating an archive with PKZIP V4.0 will take substantially more time on network 

drives than on local drives. 


24-4 A5E00706944-01


24.2.1 Uses for Saving/Archiving 

Save As 

With this function you create a copy of the project under another name. 

You can use this function: 

• To create backup copies 

• To duplicate an existing project in order to adapt it for other purposes. 

To use the fastest method of creating a copy, select the "Save As" option without 

rearranging in the dialog box. The whole file structure from the project directory 

down is copied without a check and saved under another name. 

There must be sufficient space on the data medium to store the backup copy. Do 

not attempt to save projects to diskette as there will not generally be sufficient 

space available. To transport project data on diskette use the "Archive" function. 

Saving with rearranging takes longer, but a message is displayed if an object 

cannot be copied and saved. Causes for this may be a missing optional package or 

defective data for an object. 

Archive 

You can store individual projects or libraries in compressed form in an archive file. 

This compressed storage procedure is possible on a hard disk or on a portable 

data medium (such as a floppy disk). 

Only transport projects on diskette in the form of archive files. If the project is too 

large, select an archive program with which disk-crossing archives can be created. 

Projects or libraries which were compressed into an archive file cannot be edited. If 

you want to edit them again you must unpack the data which means retrieving the 

project or library. 

24.2.2 Requirements for Archiving 

To archive a project or library, the following requirements must be fulfilled: 

• You must have installed the archive program in your system. The link to STEP 7 

is explained in the online help topic "Procedure for Archiving/Retrieving." 

• All the data for the project without exception must be in the project directory or a 

subdirectory of the project. When working with the C development environment, 

it is possible to store data in other locations. These data would then not be 

included in the archive file. 

• As of STEP 7 V5.2, only the archiving programs PKZip 4.0, JAR, WinZip are 

supported. However, for retrieval, the programs ARJ and LHArc are also 

supported. 


A5E00706944-01 24-5


24.2.3 Procedure for Archiving/Retrieving 

You archive/retrieve your project or library using the menu command File > 

Archive or File > Retrieve. 

Note 

Projects or libraries which were compressed into an archive file cannot be edited. If 

you want to edit them again you must unpack the data which means retrieving the 

project or library. 

When retrieving, the retrieved projects or libraries are automatically included in the 

project/library list. 

Setting the Target Directory 

To set the target directory, use the menu command Options > Customize in the 

SIMATIC Manager to open the "Customize" dialog box. 

In the "Archive" tab of this dialog box you can switch the option "Check target 

directory on retrieval" on and off. 

If this option is deactivated, the path set in the "General" tab of the same dialog box 

for "Storage location for projects" and "Storage location for libraries" is used as the 

target directory for retrieving. 

Copying an Archive File to Diskette 

You can archive a project/library and then copy the archive file to a diskette. It is 

also possible to select a floppy disk drive in the "Archive" dialog box as the target 

directory. 


24-6 A5E00706944-01

25 Working with M7 Programmable Control 

Systems 

25.1 Procedure for M7 Systems 

The standard PC architecture of the M7-300/M7-400 automation computer forms a 

freely programmable extension to the SIMATIC automation platform. You can 

programs the user programs for SIMATIC M7 in a high-level language such as C or 

graphically using CFC (Continuous Function Chart). 

To create the programs, you will also require the system software M7-SYS RT for 

M7-300/400 and a development environment for M7 programs (ProC/C++ or CFC) 

in addition to STEP 7. 


When you create an automation solution with SIMATIC M7, there are a series of 

basic tasks. The following table shows the tasks that need to be performed for 

most projects and assigns them to a basic procedure. The table also gives 

references to the relevant chapter in this manual or other manuals. 

Procedure 

Design automation solution 

Start STEP 7 

Create project structure 

Set up station 

Configure the hardware 

Configure communication connections 

Define symbol table 

Create C or CFC user program 

Configure operating system 

Install operating system on M7-300/M7-400 

Download hardware configuration and user program to M7 

Test and debug user program 

Monitor operation and M7 diagnostics 

Printing and archiving 

Description 

M7-specific; 

refer to: 

M7-SYS RT Programming 

Manual 

As for S7 

As for S7 

As for S7 

As for S7 

M7-specific; 

refer to: ProC/C++ 

M7-specific; 

refer to: 

M7-SYS RT User Manual 

ProC/C++ 

As for S7, but without userdefined 

diagnostics 

As for S7 


A5E00706944-01 25-1

Working with M7 Programmable Control Systems 

What Is Different in M7? 

For M7-300/M7-400, the following functions are not supported in STEP 7: 

• Multicomputing - synchronous operation of several CPUs 

• Force variables 

• Global data communication 

• User-defined diagnostics 

Managing M7 Programmable Control Systems 

STEP 7 offers you specific support with the following tasks on M7 programmable 

control systems: 

• Installing an operating system on the M7-300/M7-400 

• Configuring the operating system by editing system files 

• Downloading user programs to the M7-300/M7-400 

• Updating the firmware 

To access M7 programmable control system management, select the following 

menu command from the context of a project that contains stations with M7 CPUs 

or FMs, with the M7 program folder selected: 

PLC > Manage M7 System 

You will find detailed instructions in the online help and user manual for M7-SYS 

RT. 


25-2 A5E00706944-01


25.2 Optional Software for M7 Programming 

M7 Optional Software 

STEP 7 provides you with the basic functions you require to do the following: 

• Create and manage projects 

• Configure and assign parameters to the hardware 

• Configure networks and connections 

• Manage symbol data 

These functions are provided regardless of whether you are using a SIMATIC S7 

or SIMATIC M7 programmable controller. 

To create M7 applications, you will require the M7 optional software in addition to 

STEP 7. 

Software 

Content 

M7-SYS RT • M7 RMOS32 operating system 

• M7-API system library 

• Support for MPI 

CFC for S7 and M7 Programming software for CFC (Continuous Function Chart) 

programs 

M7-ProC/C++ • Link for the Borland development environment in STEP 7 

• Symbol import editor and generator 

• Organon xdb386 high-level language debugging tool 

Borland C++ Borland C/C++ development environment 

In conjunction with the M7 optional software, STEP 7 can also support the following 

additional tasks: 

• Downloading data to the M7 programmable control system via the multipoint 

interface (MPI) 

• Requesting information about the M7 programmable control system 

• Making particular settings on the M7 programmable control system and 

resetting the M7 


A5E00706944-01 25-3


The following figure shows the dependencies of the M7 optional software for M7 

programming. 

Summary 

To create... 

You will require the M7 software option... 

C/C++ programs 

2e M7-SYS RT 

3e M7-ProC/C++ 

4th Borland C++ 

CFC programs 1st M7-SYS RT 

2nd CFC for S7 and M7 

3rd Borland C++ 


25-4 A5E00706944-01


Which Software Offers Which Type of Support? 

The specific tools required to create M7 applications are partly integrated in 

STEP 7 and partly in the M7 software options. 

The following table shows you which software package supports which tasks: 

Software 

Support Offered 

STEP 7 • Installing the M7 operating system 

• Managing the M7 programmable control system 

• Downloading, starting, and deleting the M7 programs 

• Displaying status and diagnostic data 

• Resetting the CPU 

M7-SYS RT The M7 operating system and M7 system software utilities help with 

the following: 

• Controlling program processing 

• Managing memory and resources 

• Access to computer hardware and SIMATIC hardware 

• Handling interrupts 

• Diagnostics 

• Status monitoring 

• Communication 

M7-ProC/C++ • By integrated code creation (integrating the Borland 

development environment into STEP 7) 

• By linking project symbols into the source code 

• By integrated debugging functions 

Borland C++ • Creating C and C++ programs 

CFC for S7 and M7 • Creating, testing, and debugging CFC programs 

• Starting and running CFC programs 


A5E00706944-01 25-5


25.3 M7-300/M7-400 Operating Systems 

The utilities offered by the operating system are of prime importance for 

applications created using the high-level languages C and C++. The operating 

system takes on the following tasks for the application: 

• Accessing the hardware 

• Managing resources 

• System integration 

• Communication with other components in the system 

To solve automation tasks, the M7 RMOS32 (Realtime Multitasking Operating 

System) real-time operating system is used with the SIMATIC M7 automation 

computer. M7 RMOS32 has been extended to include a call interface, the M7 API 

(Application Programming Interface) to integrate it into the SIMATIC system. 

The real-time operating system M7 RMOS32 is used for 32-bit applications in 

time-critical, real-time, and multitasking solutions. It is available in the following 

configurations for M7 modules: 

• M7 RMOS32 

• M7 RMOS32 with MS-DOS 

The operating system configuration you choose for your M7 programmable control 

system depends on the M7 modules you are using: 


Configuration 

Module / 

Main Memory 

PROFIBUS-DP and TCP/IP 

Yes/No 

No 

Yes 

Yes 

Yes 

Yes 

Yes 

No 

No 

Yes 

Yes 

Yes 

Installation on 

Mass Memory 

Memory card ≥4 MB 

or hard disk 

M7 RMOS32 

M7 RMOS32 

with MS-DOS 

FM 356-4 / 4 MB 

FM 356-4 / 8 MB 

CPU 388-4 / 8 MB 

FM 456-4 / 16 MB 

CPU 488-3 / 16 MB 

CPU 486-3 / 16 MB 

FM 356-4 / 8 MB 

CPU 388-4 / 8 MB 

FM 456-4 / 16 MB 

CPU 488-3 / 16 MB 

CPU 486-3 / 16 MB 

Memory card ≥4 MB 

or hard disk 


25-6 A5E00706944-01

26 Tips and Tricks 

26.1 Exchanging Modules in the Configuration Table 

If you using HW Config to revise a station configuration and you want to exchange 

a module for one with a new order number for example, proceed as follows: 

1. Use a drag-and-drop operation to drag the module from the Hardware Catalog 

window over the old module that is already placed. 

2. Drop the new module. To the extent possible, the new module assumes the 

parameters of the one that was already inserted. 

This procedure is faster than exchanging modules by deleting the old module and 

then inserting the new one and assigning parameters to it. 

You can turn this function on or off in HW Config by means of the menu command 

Options > Settings ("Enable Module Swapping") 

26.2 Projects with a Large Number of Networked Stations 

If you configure all stations one after the other and then call NetPro by means of 

the menu command Options > Configure Network in order to configure 

connections, the stations are placed in the network view automatically. This 

procedure has the disadvantage that you then have to arrange the stations and 

subnets according to topological criteria later. 

If your project includes a large number of networked stations and you want to 

configure connections between these stations, you should configure the system 

structure in the network view from the beginning to preserve the overview: 

1. Create the new project in the SIMATIC Manager (menu command File > New). 

2. Start NetPro (menu command Options > Configure Network) 

3. Create in NetPro station for station as follows: 

- Use a drag-and-drop operation to place the station from the Catalog 

window. 

- Double-click the station to start HW Config. 

- Use a drag-and-drop operation to place the modules with communication 

capability (CPUs, CPs, FMs, IF modules) in HW Config. 

- If you want to network these modules, double-click on the corresponding 

rows in the configuration table to create new subnets and to network the 

interfaces. 

- Save the configuration and switch to NetPro. 

- In NetPro, position stations and subnets (move objects with the mouse 

until you have reached the position you want) 

4. Configure the connections in NetPro and correct the networking where 

necessary. 


A5E00706944-01 26-1

Tips and Tricks 

26.3 Rearranging 

If unexplained problems occur when working with STEP 7, it often helps to 

rearrange the database of the project or library. 

Select the menu command File > Rearrange to do this. This removes any gaps 

which occur when contents are deleted, meaning that the amount of memory 

required for the project/library data is reduced. 

The function optimizes the data storage for the project or library in a similar way to 

which a program defragments a hard disk also optimizes file storage on the hard 

disk. 

The duration of the reorganization process depends on the amount of data to be 

moved around and may take some time. The function is therefore not executed 

automatically (for example, when you close a project) but must be triggered by the 

user when he/she wants to rearrange the project or library. 

Requirement 

Projects and libraries can only be rearranged if no objects in them are being edited 

by other applications and therefore locked for access. 

26.4 Editing Symbols Across Multiple Networks 

The LAD/STL/FBD program editor lets you view and edit the symbols of multiple 

networks. 

1. Select a network name with a click on the network name (e.g. "Network 1"). 

2. Hold down the CRTL key and add further networks to your selection. 

3. Right-click to call the context-sensitive menu command Edit Symbols. 

Use the shortcut CTRL+A to select all networks of a block and then highlight a 

network name. 


26-2 A5E00706944-01


26.5 Testing with the Variable Table 

For monitoring and modifying variables in the variable table, note the following 

editing tips: 

• You can enter symbols and addresses in both the "Symbol" column as well as 

the "Address" column. The entry is written into the appropriate column 

automatically. 

• To display the modified value, you should set the trigger point for "Monitoring" to 

"Beginning of Scan Cycle" and the trigger point for Modifying" to "End of Scan 

Cycle." 

• If you place the cursor in a row that is marked with red, a brief information is 

displayed telling you the cause of the error. Press F1 to get suggestions for 

eliminating the error. 

• You can enter only those symbols that are already defined in the symbol table. 

You must enter a symbol exactly as it is defined in the symbol table. 

Symbol names that contain special characters must be enclosed in quotation 

marks (for example, "Motor.Off," "Motor+Off," "Motor-Off"). 

• Warnings can be switched off in the "Online" tab ("Customize" dialog box). 

• The connection can be changed without having previously disconnected the 

connection. 

• The monitoring trigger can be defined while monitoring variables. 

• You can modify selected variables by selecting the rows and executing the 

"Force" function. Only the highlighted variables are modified. 

• Exiting without Confirmation: 

If you press the ESC key while "Monitoring," "Modifying" "Release PQ," 

"Monitoring" and "Modifying" are terminated without asking if you want to exit. 

• Entering a Contiguous Address Range: 

Use the menu command Insert > Range of Variables. 

• Displaying and Hiding Columns: 

Use the following menu commands to display or hide individual columns: 

Symbol: View > Symbol 

Symbol comment: View > Symbol Comment 

Presentation format of the status value: View > Display Format 

Status value of the variables: View > Status Value 

Modify value of the variables: View > Modify Value 

• Changing the display format of several rows of the table at the same time: 

1. Select the area of the table in which you want to change the display format by 

holding the left mouse button down and dragging across the desired table area. 

2. Select the presentation with the menu command View > Select Display 

Format. The format is changed only for those rows of the selected table for 

which a format change is permitted. 

• Input examples by means of the F1 key: 

- If you place the cursor in the address column and you press F1, you will 

get examples for address inputs. 

- If you place the cursor in the modify value column and you press F1, you 

will get examples for modify/force value inputs. 


A5E00706944-01 26-3


26.6 Modifying Variables With the Program Editor 

In the program editor, you can program buttons for binary inputs and memory bits 

that offer you a quick and easy way to modify these addresses with mouse click. 

Requirements 

• In the symbol table, you have assigned this property to the address you want to 

modify via the menu command Special Object Properties > Control at 

Contact 

• You have selected the "Control at Contact" option in the "General" tab of the 

LAD/STL/FBD program editor (Menu command Options > Customize). 

• You have selected the menu command Debug > Monitor. 

Triggering condition is here "permanent/at the cycle start". 

The inputs actually available in your plant will be monitored for as long as you keep 

the button pressed. You can also modify multiple inputs via multiple selection 

(CTRL key). 

In the case of bit memories or unavailable inputs, pressing the button will cause the 

status to be set to 1. The status will only be reset to 0 if this is explicitly requested 

through a context menu entry or in the variable table, or if the address is reset by 

the STEP 7 program. 

In the case of a non-negated input or bit memory, pressing the button will cause 

the modify value "1" to apply; in the case of a negated input or bit memory, the 

modify value "0" will apply. 

Note on WinCC 

If you have started the program editor in WinCC via the operator control and 

monitoring of a variable, only the control options of WinCC are allowed. Otherwise, 

if the operator has been granted "Maintenance rights" of WinCC, both modify 

options are allowed. 

Editing the "Control at Contact" Attribute 


26-4 A5E00706944-01


26.7 Virtual Work Memory 

Another reason for problems occurring in STEP 7 may be insufficient virtual work 

memory. 

To work with STEP 7 you should adjust the setting for the virtual memory. Proceed 

as follows: 

1. Open the Control Panel, for example, via the Start menu Start > Settings > 

Control Panel and double-click on the icon "System". 

XP only: Open under START > Desktop > Properties > Advanced > System 

Performance > Settings. 

2. In Windows 2000, select the "Advanced" tab and click on the "System 

Performance Options" button. 

Under Windows XP/Server 2003, select the "Advanced" tab in the "System 

settings" dialog box. 

3. Click the "Change" button. 

4. Enter at least 40 Mbytes as the "Minimum" and at least 150 Mbytes as the 

"Maximum." 

Note 

As the virtual memory is on the hard disk (default C:) and dynamic, you should 

ensure that sufficient memory is available for the directory TMP or TEMP 

(approx. 20 to 30 Mbytes): 

• If the S7 project is also on the same partition on which the virtual memory is 

set, approximately twice the size of the S7 project should be available as free 

memory space. 

• If the project is stored on another partition, this requirement becomes 

irrelevant. 


A5E00706944-01 26-5



26-6 A5E00706944-01

A 

Appendix 

A.1 Operating Modes 

A.1.1 

Operating Modes and Mode Transitions 

Operating Modes 

Operating modes describe the behavior of the CPU at a particular point in time. 

Knowing the operating modes of CPUs is useful when programming the startup, 

testing the controller, and for troubleshooting. 

The S7-300 and S7-400 CPUs can adopt the following operating modes: 

• STOP 

• STARTUP 

• RUN 

• HOLD 

In STOP mode, the CPU checks whether all the configured modules or modules 

set by the default addressing actually exist and sets the I/Os to a predefined initial 

status. The user program is not executed in STOP mode. 

In STARTUP mode, a distinction is made between the startup types "warm restart," 

"cold restart," and "hot restart:" 

• In a warm restart, program processing starts at the beginning of the program 

with initial settings for the system data and user address areas (the nonretentive 

timers, counters, and bit memory are reset). 

• In a cold restart, the process-image input table is read in and the STEP 7 user 

program is processed starting at the first command in OB1 (also applies to 

warm restart). 

- Any data blocks created by SFC in the work memory are deleted; the 

remaining data blocks have the preset value from the load memory. 

- The process image and all timers, counters, and bit memory are reset, 

regardless of whether they were assigned as retentive or not. 


A5E00706944-01 A-1

Appendix 

• In a hot restart, the program is resumed at the point at which it was interrupted 

(timers, counters, and bit memory are not reset). A hot restart is only possible 

on S7-400 CPUs. 

In RUN mode, the CPU executes the user program, updates the inputs and 

outputs, services interrupts, and process error messages. 

In HOLD mode, processing of the user program is halted and you can test the user 

program step by step. The HOLD mode is only possible when you are testing using 

the programming device. 

In all these modes, the CPU can communicate via the multipoint interface (MPI). 

Other Operating Modes 

If the CPU is not ready for operation, it is in one of the following modes: 

• Off, in other words, the power supply is turned off. 

• Defective, in other words, a fault has occurred. 

To check whether the CPU is really defective, switch the CPU to STOP and 

turn the power switch off and then on again. If the CPU starts up, display the 

diagnostic buffer to analyze the problem. If the CPU does not start up it must 

be replaced. 

Operating Mode Transitions 

The following figure shows the operating modes and mode transitions for S7-300 

and S7-400 CPUs: 

The table shows the conditions under which the operating modes can change. 

Transition Description 

1. After you turn on the power supply, the CPU is in STOP mode. 

2. The CPU changes to STARTUP mode: 

• After the CPU is changed to RUN or RUN-P using the key switch or by 

the programming device. 

• After a startup triggered automatically by turning on the power. 

• If the RESUME or START communication function is executed. 

In both cases the key switch must be set to RUN or RUN-P. 


A-2 A5E00706944-01

Appendix 

Transition Description 

3. The CPU changes back to STOP mode when: 

• An error is detected during the startup. 

• The CPU is changed to STOP by the key switch or on the programming 

device. 

• A stop command is executed in the startup OB. 

• The STOP communication function is executed. 

4. The CPU changes to HOLD mode when a breakpoint is reached in the 

startup program. 

5. The CPU changes to STARTUP mode when the breakpoint in a startup 

program was set and the "EXIT HOLD" command was executed (test 

functions). 


• The CPU is changed to STOP with the key switch or by the 


• The STOP communication command is executed. 

7. If the startup is successful, the CPU changes to RUN. 


• An error is detected in RUN mode and the corresponding OB is not 

loaded. 

• The CPU is changed to STOP by the key switch or on the programming 

device. 

• A stop command is edited in the user program. 

• The STOP communication function is executed. 

9. The CPU changes to HOLD mode when a breakpoint is reached in the user 

program. 

10. The CPU changes to RUN mode when a breakpoint was set and the "EXIT 

HOLD" command is executed. 

Operating Mode Priority 

If a number of operating mode transitions are requested simultaneously, the 

operating mode with the highest priority is selected. If, for example, the mode 

selector is set to RUN and you attempt to set the CPU to STOP at the 

programming device, the CPU will change to STOP because this mode has the 

highest priority. 

Priority 

Highest 

Lowest 

Mode 

STOP 

HOLD 

STARTUP 

RUN 


A5E00706944-01 A-3

Appendix 

A.1.2 

STOP Mode 

The user program is not executed in STOP mode. All the outputs are set to 

substitute values so that the controlled process is in a safe state. The CPU makes 

the following checks: 

• Are there any hardware problems(for example, modules not available)? 

• Should the default setting apply to the CPU or are there parameter sets? 

• Are the conditions for the programmed startup behavior satisfied? 

• Are there any system software problems? 

In STOP mode, the CPU can also receive global data and passive one-way 

communication is possible using communication SFBs for configured connections 

and communication SFCs for not configured connections. 

Memory Reset 

The CPU memory can be reset in STOP mode. The memory can be reset manually 

using the key switch (MRES) or from the programming device (for example, before 

downloading a user program). 

Resetting the CPU memory returns the CPU to its initial status, as follows: 

• The entire user program in the work memory and in the RAM load memory and 

all address areas are cleared. 

• The system parameters and the CPU and module parameters are reset to the 

default settings. The MPI parameters set prior to the memory reset are 

retained. 

• If a memory card (Flash EPROM) is plugged in, the CPU copies the user 

program from the memory card to the work memory (including the CPU and 

module parameters if the appropriate configuration data are also on the 

memory card). 

The diagnostic buffer, the MPI parameters, the time, and the runtime meters are 

not reset. 


A-4 A5E00706944-01

Appendix 

A.1.3 

STARTUP Mode 

Before the CPU can start processing the user program, a startup program must 

first be executed. By programming startup OBs in your startup program, you can 

specify certain settings for your cyclic program. 

There are three types of startup: warm restart, cold restart, and hot restart. A hot 

restart is only possible on S7-400 CPUs. This must be set explicitly in the 

parameter set for the CPU using STEP 7. 

The features of the STARTUP mode are as follows: 

• The program in the startup OB is processed (OB100 for warm restart, OB101 

for hot restart, OB102 for cold restart). 

• No time-driven or interrupt driven program execution is possible. 

• Timers are updated. 

• Runtime meters start running. 

• Disabled digital outputs on signal modules (can be set by direct access). 

Warm Restart 

A warm restart is always permitted unless the system has requested a memory 

reset. A warm restart is the only possible option after: 

• Memory reset 

• Downloading the user program with the CPU in STOP mode 

• I stack/B stack overflow 

• Warm restart aborted (due to a power outage or changing the mode selector 

setting) 

• When the interruption before a hot restart exceeds the selected time limit. 

Manual Warm Restart 

A manual warm restart can be triggered by the following: 

• The mode selector 

(the CRST/WRST switch - if available - must be set to CRST) 

• The corresponding command on the programming device or by communication 

functions 

(if the mode selector is set to RUN or RUN-P) 


A5E00706944-01 A-5

Appendix 

Automatic Warm Restart 

An automatic warm restart can be triggered following power up in the following 

situations: 

• The CPU was not in STOP mode when the power outage occurred. 

• The mode selector is set to RUN or RUN-P. 

• No automatic hot restart is programmed following power up. 

• The CPU was interrupted by a power outage during a warm restart (regardless 

of the programmed type of restart). 

The CRST/WRST switch has no effect on an automatic warm restart. 

Automatic Warm Restart Without a Backup Battery 

If you operate your CPU without a backup battery (if maintenance-free operation is 

necessary), the CPU memory is automatically reset and a warm restart executed 

after the power is turned on or when power returns following a power outage. The 

user program must be located on a flash EPROM (memory card). 

Hot Restart 

Following a power outage in RUN mode followed by a return of power, S7-400 

CPUs run through an initialization routine and then automatically execute a hot 

restart. During a hot restart, the user program is resumed at the point at which its 

execution was interrupted. The section of user program that had not been executed 

before the power outage is known as the remaining cycle. The remaining cycle can 

also contain time-driven and interrupt driven program sections. 

A hot restart is only permitted when the user program was not modified in STOP 

mode (for example, by reloading a modified block) and when there are no other 

reasons for a warm restart. Both a manual and automatic hot restart are possible. 

Manual Hot Restart 

A manual hot restart is only possible with the appropriate parameter settings in the 

parameter set of the CPU and when the STOP resulted from the following causes: 

• The mode selector was changed from RUN to STOP. 

• User-programmed STOPs, STOPs after calling OBs that are not loaded. 

• The STOP mode was the result of a command from the programming device or 

a communication function. 

A manual hot restart can be triggered by the following: 

• The mode selector 

The CRST/WRST must be set to WRST. 

• The corresponding command on the programming device or by communication 

functions (mode selector set to RUN or RUN-P). 

• When a manual hot restart is set in the parameter set of the CPU. 


A-6 A5E00706944-01

Appendix 

Automatic Hot Restart 

An automatic hot restart can be triggered following power up in the following 

situations: 

• The CPU was not in STOP or HOLD mode when the power outage occurred. 

• The mode selector is set to RUN or RUN-P. 

• Automatic hot restart following power up is set in the parameter set of the CPU. 

The CRST/WRST switch has no effect on an automatic hot restart. 

Retentive Data Areas Following Power Down 

S7-300 and S7-400 CPUs react differently to power up following a power outage. 

S7-300 CPUs (with the exception of the CPU 318) are only capable of a warm 

restart. With STEP 7, you can, however, specify memory bits, timers, counters, and 

areas in data blocks as retentive to avoid data loss caused by a power outage. 

When the power returns, an automatic warm restart with memory is executed. 

S7-400 CPUs react to the return of power depending on the parameter settings 

either with a warm restart (following retentive or non-retentive power on) or a hot 

restart (only possible following retentive power on). 

The following table shows the data that are retained on S7-300 and S7-400 CPUs 

during a warm restart, cold restart, or hot restart. 

X means data retained 

VC means logic block retained in EPROM, any overloaded logic blocks are lost 

VX means data block is retained only if on the EPROM retentive data are taken from the 

NV-RAM (loaded or created data blocks in the RAM are lost) 

0 means data are reset or erased (content of DBs) 

V means data are set to the initialization value taken from the EPROM memory 

--- means not possible as no NV-RAM available 


A5E00706944-01 A-7

Appendix 

The following table shows the data that are retained on work memory (EPROM and RAM load 

memory): 

Data 

Warm 

restart 

on 

S7- 

300 

Warm 

restart 

on 

S7- 

400 

Cold 

restart 

on 

S7- 

300 

Cold 

restart 

on 

S7- 

400 

Hot 

restart 

on S7- 

400 

EPROM (Memory Card or Integrated) 

CPU with Backup Battery CPU without Backup Battery 

Blocks in 

load 

memory 

DB in 

work 

memory 

Memory 

bits, 

timers, 

counters 

(defined 

as 

retentive) 

Memory 

bits, 

timers, 

counters 

(defined 

as 

volatile) 

Blocks 

in load 

memory 

DB in 

work 

memory 

(defined 

as retentive) 

DB in 

work 

memory 

(defined 

as 

volatile) 

Memory 

bits, 

timers, 

counters 

(defined 

as retentive) 

X X X 0 VC VX V X 0 

X X X 0 VC --- V 0 0 

X 0 0 0 VC V V 0 0 

X 0 0 0 VC --- V 0 0 

X X X X Only warm 

restart 

permitted 

Memory 

bits, 

timers, 

counters 

(defined 

as 

volatile) 


A-8 A5E00706944-01

Appendix 

Startup Activities 

The following table shows which activities are performed by the CPU during 

startup: 

Activities in Order of Execution 

In Warm 

Restart 

In Cold Restart In Hot Restart 

Clear I stack/B stack X X 0 

Clear volatile memory bits, timers, counters X 0 0 

Clear all memory bits, timers, counters 0 X 0 

Clear process-image output table X X selectable 

Reset outputs of digital signal modules X X selectable 

Discard hardware interrupts X X 0 

Discard time-delay interrupts x x 0 

Discard diagnostic interrupts X X X 

Update the system status list (SZL) X X X 

Evaluate module parameters and transfer to 

modules or transfer default values 

X X X 

Execution of the relevant startup OB X X X 

Execute remaining cycle (part of the user 

program not executed due to the power 

down) 

0 0 X 

Update the process-image input table X X X 

Enable digital outputs (cancel OD signal) after 

transition to RUN 

X means is performed 

0 means is not performed 

X X X 


A5E00706944-01 A-9

Appendix 

Aborting a Startup 

If an error occurs during startup, the startup is aborted and the CPU changes to or 

remains in STOP mode. 

An aborted warm restart must be repeated. After an aborted restart, both a warm 

restart and a hot restart are possible. 

A startup (restart (warm restart) or hot restart) is not executed or it is aborted in the 

following situations: 

• The operating mode switch of the CPU is set to STOP. 

• A memory reset is requested. 

• A memory card with an application code that is not permitted for STEP 7 is 

plugged in (for example, STEP 5). 

• More than one CPU is inserted in the single processor mode. 

• If the user program contains an OB that the CPU does not recognize or that 

has been disabled. 

• If, after power on, the CPU recognizes that not all the modules listed in the 

configuration table created with STEP 7 are actually inserted (difference 

between preset and actual parameter assignment not permitted). 

• If errors occur when evaluating the module parameters. 

A hot restart is not executed or it is aborted in the following situations: 

• The CPU memory was reset (only a warm restart is possible after memory 

reset). 

• The interruption time limit has been exceeded (this is the time between exiting 

RUN mode until the startup OB including the remaining cycle has been 

executed). 

• The module configuration has been changed (for example module replaced). 

• The parameter assignment only permits a warm restart. 

• When blocks have been loaded, deleted, or modified while the CPU was in 

STOP mode. 


A-10 A5E00706944-01

Appendix 

Sequence of Activities 

The following figure shows the activities of the CPU during STARTUP and RUN: 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 A-11

Appendix 

Key to the figure "Activities of the CPU during STARTUP and RUN" 

1. All peripheral outputs are switched to a safe state (default value = 0) on the 

hardware side by the I/O modules. This switch takes place regardless of 

whether the user program employs the outputs inside the process-image area 

or outside of it. 

If you are using signal modules that have substitute value capability, you 

can assign parameters to the behavior of the outputs, such as Keep Last 

Value. 

2. Necessary for processing the remaining scan cycle. 

3. A current process-image input table is also available to the interrupt OBs the 

first time that they are called up. 

4. You can determine the status of the local and distributed peripheral outputs in 

the first scan cycle of the user program by taking the following steps: 

- Use output modules to which you can assign parameters to enable the 

output of substitute values or to keep the last value. 

- For a hot restart: activate the CPU startup parameter "Reset outputs during 

hot restart" in order to output a 0 (corresponds to the default setting). 

- Preset the outputs in the startup OB (OB100, OB101, OB102). 

5. In S7-300 systems that are not backed up, only those DB areas that were 

configured as retentive are retained. 


A-12 A5E00706944-01

Appendix 

A.1.4 

RUN Mode 

In RUN mode, the CPU executes the cyclic, time-driven, and interrupt-driven 

program, as follows: 

• The process image of the inputs is read in. 

• The user program is executed. 

• The process-image output table is output. 

The active exchange of data between CPUs using global data communication 

(global data table) and using communication SFBs for configured connections and 

using communication SFCs for non-configured connections is only possible in RUN 

mode. 

The following table shows an example of when data exchange is possible in 

different operating modes: 

Type of Communication 

Mode of CPU 1 Direction of Data 

Exchange 

Mode of CPU 2 

Global data communication RUN ↔ RUN 

RUN → STOP/HOLD 

STOP ← RUN 

STOP X STOP 

HOLD X STOP/HOLD 

One-way communication RUN → RUN 

with communication SFBs RUN → STOP/HOLD 

Two-way with communication 

SFBs 

RUN ↔ RUN 

One-way communication RUN → RUN 

with communication SFCs RUN → STOP/HOLD 

Two-way with communication 

SFCs 

↔ means data exchange is possible in both directions 

→ means data exchange is possible in only one direction 

X means data exchange is not possible 

RUN ↔ RUN 


A5E00706944-01 A-13

Appendix 

A.1.5 

HOLD Mode 

The HOLD mode is a special mode. This is only used for test purposes during 

startup or in RUN mode. The HOLD mode means the following: 

• All timers are frozen: timers and runtime meters are not processed, monitoring 

times are stopped, the basic clock pulses of the time-driven levels are stopped. 

• The real-time clock runs. 

• Outputs are not enabled but can be enabled explicitly for test purposes. 

• Inputs and outputs can be set and reset. 

• If a power outage occurs on a CPU with a backup battery while in HOLD mode, 

the CPU changes to stop when the power returns but does not execute an 

automatic hot restart or restart (warm restart). CPUs without battery backup 

execute an automatic restart (warm restart) when power returns. 

• Global data can be received and passive one-way communication using 

communication SFBs for configured connections and communication SFCs for 

non-configured connections is possible (see also table in RUN Mode). 


A-14 A5E00706944-01

Appendix 

A.2 Memory Areas of S7 CPUs 

A.2.1 

Distribution of the Memory Areas 

The memory of an S7 CPU can be divided into three areas (see figure below): 

• The load memory is used for user programs without symbolic address 

assignments or comments (these remain in the memory of the programming 

device). The load memory can be either RAM or EPROM. 

• Blocks that are not marked as required for startup will be stored only in the load 

memory. 

• The work memory (integrated RAM) contains the parts of the S7 program 

relevant for running your program. The program is executed only in the work 

memory and system memory areas. 

• The system memory (RAM) contains the memory elements provided by every 

CPU for the user program, such as the process-image input and output tables, 

bit memory, timers, and counters. The system memory also contains the block 

stack and interrupt stack. 

• In addition to the areas above, the system memory of the CPU also provides 

temporary memory (local data stack) that contains temporary data for a block 

when it is called. This data only remains valid as long as the block is active. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 A-15

Appendix 

A.2.2 

Load Memory and Work Memory 

When you download the user program from the programming device to the CPU, 

only the logic and data blocks are loaded in the load and work memory of the CPU. 

The symbolic address assignment (symbol table) and the block comments remain 

on the programming device. 

Dividing Up the User Program 

To ensure fast execution of the user program and to avoid unnecessary load on the 

work memory that cannot be expanded, only the parts of the blocks relevant for 

program execution are loaded in the work memory. 

Parts of blocks that are not required for executing the program (for example, block 

headers) remain in the load memory. 

The following figure shows a program being loaded in the CPU memory. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Note 

Data blocks that are created in the user program with the help of system functions 

(for example, SFC22 CREAT_DB) are saved entirely in the work memory by the 

CPU. 

Some CPUs have separately managed areas for code and data in the work 

memory. The size and assignment of these areas is shown in the "Memory" tab of 

the Module Information for these CPUs. 


A-16 A5E00706944-01

Appendix 

Identifying Data Blocks as "Not Relevant for Execution" 

Data blocks that were programmed in a source file as part of an STL program can 

be identified as "Not Relevant for Execution" (keyword UNLINKED). This means 

that when they are downloaded to the CPU, the DBs are stored only in the load 

memory. The content of such blocks can, if necessary, be copied to the work 

memory using SFC20 BLKMOV. 

This technique saves space in the work memory. The expandable load memory is 

then used as a buffer (for example, for formulas for a mixture: only the formula for 

the next batch is loaded in the work memory). 

Load Memory Structure 

The load memory can be expanded using memory cards. Refer to your "S7-300 

Programmable Controller, Hardware and Installation Manual" and your "S7-400, 

M7-400 Programmable Controllers Module Specifications Reference Manual" for 

the maximum size of the load memory. 

The load memory can also have an integrated EPROM part as well as an 

integrated RAM part in S7-300 CPUs. Areas in data blocks can be declared as 

retentive by assigning parameters in STEP 7 (see Retentive Memory Areas on 

S7-300 CPUs). 

In S7-400 CPUs, it is imperative that you use a memory card (RAM or EPROM) to 

expand the load memory. The integrated load memory is a RAM memory and is 

mainly used to reload and correct blocks. With the new S7-400 CPUs, additional 

work memory can also be plugged in. 

Load Memory Behavior in RAM and EPROM Areas 

Depending on whether you select a RAM or an EPROM memory card to expand 

the load memory, the load memory may react differently during downloading, 

reloading, or memory reset. 

The following table shows the various loading methods: 

Memory Type Method of Loading Type of Loading 

RAM 

Downloading and deleting individual PG-CPU connection 

blocks 

Integrated (S7-300 

only) or plug-in 

EPROM 

Downloading and deleting an entire S7 

program 

Reloading individual blocks 

Downloading entire S7 programs 

PG-CPU connection 



Plug-in EPROM Downloading entire S7 programs Uploading the EPROM to 

the PG and inserting the 

memory card in the CPU 

Downloading the EPROM 

to the CPU 

Programs stored in RAM are lost when you reset the CPU memory (MRES) or if 

you remove the CPU or RAM memory card. 

Programs saved on EPROM memory cards are not erased by a CPU memory 

reset and are retained even without battery backup (transport, backup copies). 


A5E00706944-01 A-17

Appendix 

A.2.3 

A.2.3.1 

System Memory 

Using the System Memory Areas 

The system memory of the S7 CPUs is divided into address areas (see table 

below). Using instructions in your program, you address the data directly in the 

corresponding address area. 

Address Area 

Access via Units of 

Following Size 

S7 Notation 

(IEC) 

Description 

Process image input 

table 

Input (bit) 

Input byte 

Input word 

Input double word 

I 

IB 

IW 

ID 

At the beginning of the scan cycle, 

the CPU reads the inputs from the 

input modules and records the values 

in this area. 

Process image 

output table 

Output (bit) 

Output byte 

Output word 

Output double word 

Q 

QB 

QW 

QD 

During the scan cycle, the program 

calculates output values and places 

them in this area. At the end of the 

scan cycle, the CPU sends the 

calculated output values to the output 

modules. 

Bit memory 

Memory (bit) 

Memory byte 

Memory word 

Memory double word 

M 

MB 

MW 

MD 

This area provides storage for interim 

results calculated in the program. 

Timers Timer (T) T This area provides storage for timers. 

Counters Counter (C) C This area provides storage for 

counters. 

Data block 

Local data 

Data block, opened with 

"OPN DB": 

Data bit 

Data byte 

Data word 

Data double word 

Data block, opened with 

"OPN DI": 

Data bit 

Data byte 

Data word 

Data double word 

Local data bit 

Local data byte 

DB 

DBX 

DBB 

DBW 

DBD 

DI 

DIX 

DIB 

DIW 

DID 

L 

LB 

Data blocks contain information for 

the program. They can be defined for 

general use by all logic blocks 

(shared DBs) or they are assigned to 

a specific FB or SFB (instance DB). 

This area contains the temporary 

data of a block while the block is 


A-18 A5E00706944-01

Appendix 

Address Area 

Access via Units of 

Following Size 

Local data word 

Local data double word 

S7 Notation 

(IEC) 

LW 

LD 

Description 

being executed. The L stack also 

provides memory for transferring 

block parameters and for recording 

interim results from Ladder Logic 

networks. 

Peripheral (I/O) 

area: 

inputs 

Peripheral (I/O) 

area: 

Peripheral input byte PIB The peripheral input and output areas 

allow direct access to central and 

distributed input and output modules 

(DP). 

Peripheral input word 

Peripheral input double 

word 

Peripheral output byte 

PIW 

PID 

PQB 

outputs 

Peripheral output word 

Peripheral output double 

word 

PQW 

PQD 

Refer to the following CPU manuals or instruction lists for information on which 

address areas are possible for your CPU: 

• "S7-300 Programmable Controller, Hardware and Installation" Manual 

• "S7-400, M7-400 Programmable Controllers, Module Specifications" Reference 

Manual 

• "S7-300 Programmable Controller, Instruction List" 

• "S7-400 Programmable Controller, Reference Guide" 


A5E00706944-01 A-19

Appendix 

A.2.3.2 

Process-Image Input/Output Tables 

If the input (I) and output (Q) address areas are accessed in the user program, the 

program does not scan the signal states on the digital signal modules but accesses 

a memory area in the system memory of the CPU and distributed I/Os. This 

memory area is known as the process image. 

Updating the Process Image 

The following figure shows the processing steps within a scan cycle. 

One of the internal tasks of the operating system (OS) is to read the status of 

inputs into the process image input table (PII). Once this step is complete, the user 

program is executed with all blocks that are called in it. The cycle ends with writing 

the process image output table (PIQ) to the outputs for the modules. Reading in the 

process image input table and writing the process image output table to the outputs 

for the modules is all independently controlled by the operating system. 


A-20 A5E00706944-01

Appendix 

One of the internal tasks of the operating system (OS) is to write the process image 

output table (PIQ) to the outputs for the modules and to read in the status of inputs 

into the process image input table (PII). Once this step is complete, the user 

program is executed with all blocks that are called in it. Writing the process image 

output table to the outputs for the modules and reading in the process image input 

table is all independently controlled by the operating system. 

Advantages of the Process Image 

Compared with direct access to the input/output modules, the main advantage of 

accessing the process image is that the CPU has a consistent image of the 

process signals for the duration of one program cycle. If a signal state on an input 

module changes while the program is being executed, the signal state in the 

process image is retained until the process image is updated again in the next 

cycle. The process of repeatedly scanning an input signal within a user program 

ensures that consistent input information is always available. 

Access to the process image also requires far less time than direct access to the 

signal modules since the process image is located in the internal memory of the 

CPU. 

Part Process Images (Process-Image Partitions) 

In addition to having the process image (process-image input table, PII, and 

process-image output table, PIQ) automatically updated by the operating system, 

you can assign parameters to a maximum of 15 partial process images for an 

S7-400 CPU (CPU-specific, no. 1 to no. 15, see the S7-400, M7-400 

Programmable Controllers Module Specifications Reference Manual). This means 

that you can update sections of the process-image table, when necessary, 

independently of the cyclic updating of the process image table. 

Each input/output address that you assign with STEP 7 to a process-image 

partition no longer belongs to the OB1 process-image input/output tables. Input and 

output address can only be assigned once through the OB 1 process image and all 

process-image partitions. 

You define process-image partition with STEP 7 when you assign addresses 

(which input/output addresses of the modules are listed in which process-image 

partition). The process-image partition is updated either by the user with SFCs or 

automatically by the system by connecting to an OB. 

Exception: Process image partitions for synchronous cycle interrupt OBs are not 

updated on the system side, even though they are linked to an OB (OB 61 to 

OB 64). 

Note 

For S7-300 CPUs, unassigned process-image inputs and outputs can be used as 

additional bit memory areas. Programs that use this capability can run on older 

(that is, before 4/99) S7-400 CPUs only under one of the following conditions: 

For these S7-400 CPUs 

• The process image areas used as bit memory must be located outside of the 

parameter assignment for "Size of the Process Image" or. 

• must be located in a process-image partition that is updated neither by the 

system nor by SFC26/SFC27. 


A5E00706944-01 A-21

Appendix 

Updating Part Process Images (Process-Image Partitions) with SFCs 

You can use SFCs to update the entire process image or a process-image partition 

from your user program. 

• Requirement: The process image in question is not updated by the system. 

• SFC26 UPDAT_PI: Update process-image input table 

• SFC27 UPDAT_PO: Update process-image output table. 

System Update of the Part Process Images (Process-Image Partitions) 

You can also have the system update process-image partitions automatically by 

calling an OB - similar to the (entire) process image, which is updated cyclically 

before or after OB1 is processed. You can assign this function as a parameter only 

for specific CPUs. 

During operation, the assigned process-image partition is updated automatically: 

• Before the OB is processed, the process-image partition for inputs 

• After the OB is processed, the process-image partition for the outputs 

You assign the parameters for the CPU, along with the priority of the OBs, to 

indicate which process-image partition is assigned to which OB. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A-22 A5E00706944-01

Appendix 

I/O Access Error (PZF) during Update of the Process Image 

The default reaction of the CPU families (S7-300 and S7-400) to an error during 

the update of the process image varies: 

• S7-300: No entry is made in the diagnostic buffer, no OB is called, the 

corresponding input bytes are reset to "0" and will remain at "0" until the fault is 

gone again. 

• S7-400: An entry is made in the diagnostic buffer and OB85 is started for each 

I/O access for each update of the corresponding process image. The faulty 

input bytes are reset to "0" each time the process image is accessed. 

For new CPUs (as of 4/99), you can reassign parameters for the reaction to I/O 

access errors so that the CPU functions in one of the following manners: 

• Generates an entry in the diagnostic buffer and starts OB85 only for incoming 

and outgoing PZF (before OB 85 is called, the faulty input bytes are reset to "0" 

and are no longer overwritten by the operating system until the outgoing PZF) 

• Produces the default reaction of an S7-300 (does not call OB85; the 

corresponding input bytes are reset to "0" and are no longer overwritten by the 

operating system until the fault is cleared.) 

• Produces the default reaction of an S7-400 (calls OB85 for each individual 

access; the faulty input bytes are reset to "0" each time the process image is 

accessed.) 

How Often Does OB85 Start? 

In addition to the reaction to PZF that is assigned as a parameter 

(incoming/outgoing, or for each I/O access), the address space of a module also 

influences how often OB85 starts: 

For a module with an address space of up to a double word, OB85 starts once, for 

example, for a digital module with a maximum of 32 inputs or outputs, or for an 

analog module with two channels. 

For modules with a larger address space, OB85 starts as often as access has to be 

made to it with double word commands, for example, twice for an analog module 

with four channels. 


A5E00706944-01 A-23

Appendix 

A.2.3.3 

Local Data Stack 

The L stack saves the following: 

• The temporary variables of the local data of blocks 

• The start information of the organization blocks 

• Information about transferring parameters 

• Interim results of the logic in Ladder Logic programs 

When you are programming organization blocks, you can declare temporary 

variables (TEMP) that are only available when the block is executed and are then 

overwritten again. Before you access the local data stack for the first time, the local 

data must be initialized. In addition to this, every organization block also requires 

20 bytes of local data for its start information. 

The CPU has a limited amount of memory for the temporary variables (local data) 

of blocks currently being executed. The size of this memory area, the local data 

stack, is dependent on the CPU. The local data stack is divided up equally among 

the priority classes (default). This means that every priority class has its own local 

data area, thus guaranteeing that higher priority classes and their OBs also have 

space available for their local data. 

The following figure shows the assignment of local data to the priority classes in an 

example in which in the L stack OB1 is interrupted by OB10 which is then 

interrupted by OB81. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

! 

Caution 

All the temporary variables (TEMP) of an OB and its associated blocks are saved 

in the L stack. If you use too many nesting levels when executing your blocks, the 

L stack can overflow. 

S7 CPUs change to STOP mode if the permitted L stack size for a program is 

exceeded. 

Test the L stack (the temporary variables) in your program. 

The local data requirements of synchronous error OBs must be taken into 

consideration. 


A-24 A5E00706944-01

Appendix 

Assigning Local Data to Priority Classes 

Not every priority class requires the same amount of memory in the local data 

stack. By assigning parameters in STEP 7, you can set different sized local data 

areas for the individual priority classes for S7-400 CPUs and for the CPU 318. Any 

priority classes you do not required can be deselected. With S7-400 CPUs and the 

CPU 318 the memory area for other priority classes is then increased. Deactivated 

OBs are ignored during program execution and save cycle time. 

With the other S7-300 CPUs every priority class is assigned a fixed amount of local 

data (256 bytes) that cannot be changed. 

A.2.3.4 

Interrupt Stack 

If program execution is interrupted by a higher priority OB, the operating system 

saves the current contents of the accumulators and address registers, and the 

number and size of the open data blocks in the interrupt stack. 

Once the new OB has been executed, the operating system loads the information 

from the I stack and resumes execution of the interrupted block at the point at 

which the interrupt occurred. 

When the CPU is in STOP mode, you can display the I stack on a programming 

device using STEP 7. This allows you to find out why the CPU changed to STOP 

mode. 


A5E00706944-01 A-25

Appendix 

A.2.3.5 

Block Stack 

If processing of a block is interrupted by the call of another block or by a higher 

priority class (interrupt/error servicing), the B stack stores the following data: 

• Number, type (OB, FB, FC, SFB, SFC), and return address of the block that 

was interrupted. 

• Numbers of the data blocks (from the DB and DI register) that were open when 

the block was interrupted. 

Using this data, the user program can then be resumed after the interrupt. 

If the CPU is in STOP mode, you can display the B stack with STEP 7 on a 

programming device. The B stack lists all the blocks that had not been completely 

executed when the CPU changed to STOP mode. The blocks are listed in the order 

in which processing was started (see figure below). 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Block Registers 

There are two data block registers. These contain the numbers of opened data 

blocks, as follows: 

• The DB register contains the number of the open shared data block 

• The DI register contains the number of the open instance data block. 


A-26 A5E00706944-01

Appendix 

A.2.3.6 

Diagnostic Buffer 

The diagnostic buffer displays the diagnostic messages in the order in which they 

occur. The first entry contains the newest event. The number of entries in the 

diagnostic buffer is dependent on the module and its current operating mode. 

Diagnostic events include the following: 

• Faults on a module 

• Errors in the process wiring 

• System errors in the CPU 

• Mode transitions on the CPU 


• User-defined diagnostic events (via the system function SFC52). 

A.2.3.7 

Evaluating the Diagnostic Buffer 

One part of the system status list is the diagnostic buffer that contains more 

information about system diagnostic events and User-defined diagnostic events in 

the order in which they occurred. The information entered in the diagnostic buffer 

when a system diagnostic event occurs is identical to the start information 

transferred to the corresponding organization block. 

You cannot clear the entries in the diagnostic buffer and its contents are retained 

even after a memory reset. 

The diagnostic buffer provides you with the following possibilities: 

• If the CPU changes to STOP mode, you can evaluate the last events leading 

up to the STOP and locate the cause. 

• The causes of errors can be detected far more quickly increasing the 

availability of the system. 

• You can evaluate and optimize the dynamic system response. 

Organizing the Diagnostic Buffer 

The diagnostic buffer is designed to act as a ring buffer for a maximum number of 

entries which is dependent on the individual module. This means that when the 

maximum number of entries is reached, the next diagnostic buffer event causes the 

oldest entry to be deleted. All entries then move back one place. This means that 

the newest entry is always the first entry in the diagnostic buffer. For the S7-300 

CPU 314 the number of possible entries is 100: 

The number of entries displayed in the diagnostic buffer is dependent on the 

module and its current operating mode. With some CPUs, it is possible to set the 

length of the diagnostic buffer. 


A5E00706944-01 A-27

Appendix 

Diagnostic Buffer Content 

The upper list box contains a list of all the diagnostic events that occurred with the 

following information: 

• Serial number of the entry (the newest entry has the number 1) 

• Time and date of the diagnostic event: The time and date of the module are 

displayed if the module has an integrated clock. For the time data in the buffer 

to be valid, it is important that you set the time and date on the module and 

check it regularly. 

• Short description of the diagnostic event 

In the lower text box, all the additional information is displayed for the event 

selected in the list in the upper window. This information includes: 

• Event number 

• Description of the event 

• Mode transition caused by the diagnostic event 

• Reference to the location of the error in a block (block type, block number, 

relative address) which caused the entry in the buffer 

• Event state being entered or left 

• Additional information specific to the event 

With the "Help on Event" button you can display additional information on the event 

selected in the upper list box. 

Information on event IDs can be found in the Reference Help on System Blocks 

and System Functions (Jumps to Language Descriptions and Help on Blocks, 

System Attributes) 

Saving the Contents in a Text File 

Using the "Save As" button in the "Diagnostic Buffer" tab of the "Module 

Information" dialog box you can save the contents of the diagnostic buffer as ASCII 

text. 

Displaying the Diagnostic Buffer 

You can display the contents of the diagnostic buffer on the programming device 

via the "Diagnostic Buffer" tab in the "Module Information" dialog box or in a 

program using the system function SFC51 RDSYSST. 

Last Entry before STOP 

You can specify that the last diagnostic buffer entry before the transition from RUN 

to STOP is automatically sent to a logged on monitoring device (for example, PG, 

OP, TD) in order to locate and remedy the cause of the change to STOP more 

quickly. 


A-28 A5E00706944-01

Appendix 

A.2.3.8 

Retentive Memory Areas on S7-300 CPUs 

If a power outage occurs or the CPU memory is reset (MRES), the memory of the 

S7-300 CPU (dynamic load memory (RAM), work memory, and system memory) is 

reset and all the data previously contained in these areas is lost. With S7-300 

CPUs, you can protect your program and its data in the following ways: 

• You can protect all the data in the load memory, work memory, and in parts of 

the system memory with battery backup. 

• You can store your program in the EPROM (either memory card or integrated 

on the CPU, refer to the "S7-300 Programmable Controller, Hardware and 

Installation" Manual). 

• You can store a certain amount of data depending on the CPU in an area of 

the nonvolatile NVRAM. 

Using the NVRAM 

Your S7-300 CPU provides an area in the NVRAM (non-volatile RAM) (see figure 

below). If you have stored your program in the EPROM of the load memory, you 

can save certain data (if there is a power outage or when the CPU changes from 

STOP to RUN) by configuring your CPU accordingly. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

To do this set the CPU so that the following data are saved in the nonvolatile RAM: 

• Data contained in a DB (this is only useful if you have also stored your program 

in an EPROM of the load memory) 

• Values of timers and counters 

• Data saved in bit memory. 

On every CPU, you can save a certain number of timers, counters, and memory 

bits. A specific number of bytes is also available in which the data contained in DBs 

can be saved. 

The MPI address of your CPU is stored in the NVRAM. This makes sure that your 

CPU is capable of communication following a power outage or memory reset. 

Using Battery Backup to Protect Data 

By using a backup battery, the load memory and work memory are retentive during 

a power outage. If you configure your CPU so that timers, counters, and bit 

memory are saved in the NVRAM, this information is also retained regardless of 

whether you use a backup battery or not. 


A5E00706944-01 A-29

Appendix 

Configuring the Data of the NVRAM 

When you configure your CPU with STEP 7, you can decide which memory areas 

will be retentive. 

The amount of memory that can be configured in the NVRAM depends on the CPU 

you are using. You cannot back up more data than specified for your CPU. 

A.2.3.9 


Operation Without Battery Backup 

If you operate your system without battery backup, when a power outage occurs or 

when you reset the CPU memory (MRES), the memory of the S7-400 CPU 

(dynamic load memory (RAM), work memory, and system memory) is reset and all 

the data contained in these areas is lost. 

Without battery backup, only a restart (warm restart) is possible and there are no 

retentive memory areas. Following a power outage, only the MPI parameters (for 

example, the MPI address of the CPU) are retained. This means that the CPU 

remains capable of communication following a power outage or memory reset. 

Operation With Battery Backup 

If you use a battery to back up your memory: 

• The entire content of all RAM areas is retained when the CPU restarts 

following a power outage. 

• During a restart (warm restart), the address areas for bit memory, timers, and 

counters is cleared. The contents of data blocks are retained. 

• The contents of the RAM work memory are also retained apart from bit 

memory, timers, and counters that were designed as non-retentive. 

Configuring Retentive Data Areas 

You can declare a certain number of memory bits, timers, and counters as 

retentive (the number depends on your CPU). During a restart (warm restart) when 

you are using a backup battery, this data is also retained. 

When you assign parameters with STEP 7, you define which memory bits, timers, 

and counters should be retained during a restart (warm restart). You can only back 

up as much data as is permitted by your CPU. 

For more detailed information about defining retentive memory areas, refer to your 

"S7-400, M7-400 Programmable Controllers, Module Specifications" Reference 

Manual. 


A-30 A5E00706944-01

Appendix 

Configurable Memory Objects in the Work Memory 

With some CPUs the size of objects such as local data or the diagnostic buffer can 

be set under "Configuring Hardware." If, for example, reduce the size of the preset 

values, a larger percentage of the work memory will be available elsewhere. You 

will find the settings for these CPUs in the "Memory" tab of the "Module 

Information" dialog box ("Details" button). 

When you change the memory configuration and download the new configuration 

to the programmable controller, a cold restart is required on the CPU for the 

changes to come into effect. 

A.2.3.10 Configurable Memory Objects in the Work Memory 

With some CPUs, the size of objects such as local or the diagnostic buffer can be 

set in HW Config. If, for example, you reduce the default values, a larger section of 

the work memory is made available elsewhere. The settings for these CPUs can be 

displayed in the "Memory" tab of the Module Information ("Details" button). 

After the memory configuration has been changed and downloaded to the 

programmable controller, you must perform a cold restart in order for the changes 

to become effective. 


A5E00706944-01 A-31

Appendix 

A.3 Data Types and Parameter Types 

A.3.1 

Introduction to Data Types and Parameter Types 

All the data in a user program must be identified by a data type. The following data 

types are available: 

• Elementary data types provided by STEP 7 

• Complex data types that you yourself can create by combining elementary data 

types 

• Parameter types with which you define parameters to be transferred to FBs or 

FCs 

General Information 

Statement List, Ladder Logic, and Function Block Diagram instructions work with 

data objects of specific sizes. Bit logic instructions work with bits, for example. 

Load and transfer instructions (STL) and move instructions (LAD and FBD) work 

with bytes, words, and double words. 

A bit is a binary digit "0" or "1." A byte is made up of eight bits, a word of 16 bits, 

and a double word of 32 bits. 

Math instructions also work with bytes, words, or double words. In these byte, 

word, or double word addresses you can code numbers of various formats such as 

integers and floating-point numbers. 

When you use symbolic addressing, you define symbols and specify a data type for 

these symbols (see table below). Different data types have different format options 

and number notations. 

This chapter describes only some of the ways of writing numbers and constants. 

The following table lists the formats of numbers and constants that will not be 

explained in detail. 

Format Size in Bits Number Notation 

Hexadecimal 8, 16, and 32 B#16#, W#16#, and DW#16# 

Binary 8, 16, and 32 2# 

IEC date 16 D# 

IEC time 32 T# 

Time of day 32 TOD# 

Character 8 'A' 


A-32 A5E00706944-01

Appendix 

A.3.2 

Elementary Data Types 

Type and 

Description 

Each elementary data type has a defined length. The following table lists the 

elementary data types. 

Size 

in 

Bits 

Format Options Range and Number Notation 

(lowest to highest value)_ 

Example 

BOOL(Bit) 1 Boolean text TRUE/FALSE TRUE 

BYTE 

(Byte) 

8 Hexadecimal 

number 

B#16#0 to B#16#FF 

L B#16#10 

L byte#16#10 

WORD 

(Word) 

DWORD 

(Double 

word) 

INT 

(Integer) 

DINT 

(Integer, 32 

bits) 

REAL 

(Floatingpoint 

number) 

S5TIME 

(SIMATIC 

time) 

TIME 

(IEC time) 

DATE 

(IEC date) 

TIME_OF_D 

AY (Time) 

CHAR 

(Character) 

16 Binary number 

Hexadecimal 

number 

BCD 

Decimal number 

unsigned 

32 Binary number 

Hexadecimal 

number 

Decimal number 

unsigned 

16 Decimal number 

signed 

32 Decimal number 

signed 

32 IEEE 

Floating-point 

number 

16 S7 time in 

steps of 

10 ms (default) 

32 IEC time in steps 

of 1 ms, integer 

signed 

16 IEC date in steps 

of 1 day 

32 Time in steps of 

1 ms 

2#0 to 

2#1111_1111_1111_1111 

W#16#0 to W#16#FFFF 

C#0 to C#999 

B#(0.0) to B#(255.255) 

2#0 to 

2#1111_1111_1111_1111 

1111_1111_1111_1111 

DW#16#0000_0000 to 

DW#16#FFFF_FFFF 

B#(0,0,0,0) to 

B#(255,255,255,255) 

-32768 to 32767 L 1 

L#-2147483648 to 

L#2147483647 

Upper limit: ±3.402823e+38 

Lower limit: ±1.175 495e-38 

S5T#0H_0M_0S_10MS to 

S5T#2H_46M_30S_0MS and 

S5T#0H_0M_0S_0MS 

-T#24D_20H_31M_23S_648MS 

to 

T#24D_20H_31M_23S_647MS 

D#1990-1-1 to 

D#2168-12-31 

TOD#0:0:0.0 to 

TOD#23:59:59.999 

L 2#0001_0000_0000_0000 

L W#16#1000 

L word#16#1000 

L C#998 

L B#(10,20) 

L byte#(10,20) 

2#1000_0001_0001_1000_ 

1011_1011_0111_1111 

L DW#16#00A2_1234 

L dword#16#00A2_1234 

L B#(1, 14, 100, 120) 

L byte#(1,14,100,120) 

L L#1 

8 ASCII characters 'A','B' etc. L 'E' 

L 1.234567e+13 

L S5T#0H_1M_0S_0MS 

L 

S5TIME#0H_1H_1M_0S_0M 

S 

L T#0D_1H_1M_0S_0MS 

L 

TIME#0D_1H_1M_0S_0MS 

L D#1996-3-15 

L DATE#1996-3-15 

L TOD#1:10:3.3 

L TIME_OF_DAY#1:10:3.3 


A5E00706944-01 A-33

Appendix 

A.3.2.1 

Format of the Data Type INT (16-Bit Integers) 

An integer has a sign that indicates whether it is a positive or negative integer. The 

space that an integer (16 bits) occupies in the memory is one word. The following 

table shows the range of an integer (16 bits). 

Format 

Range 

Integer (16 bits) -32 768 to +32 767 

The following figure shows the integer +44 as a binary number. 

 

 

 

 

A.3.2.2 

Format of the Data Type DINT (32-Bit Integers) 

An integer has a sign that indicates whether it is a positive or negative integer. The 

space that a double integer occupies in the memory is two words. The following 

table shows the range of a double integer. 

Format 

Range 

Integer (32 bits) -2 147 483 648 to +2 147 483 647 

The following figure shows the integer -500 000 as a binary number. In the binary 

system, the negative form of an integer is represented as the twos complement of 

the positive integer. You obtain the twos complement of an integer by reversing the 

signal states of all bits and then adding +1 to the result. 

 

 

 

 


A-34 A5E00706944-01

Appendix 

A.3.2.3 

Format of the Data Type REAL (Floating-Point Numbers) 

Numbers in floating-point format are represented in the general form 

"number = m * b to the power of E." The base "b" and the exponent "E" are 

integers; the mantissa "m" is a rational number. 

This type of number representation has the advantage of being able to represent 

both very large and very small values within a limited space. With the limited 

number of bits for the mantissa and exponent, a wide range of numbers can be 

covered. 

The disadvantage is in the limited accuracy of calculations. For example, when 

forming the sum of two numbers, the exponents must be matched by shifting the 

mantissa (hence floating decimal point) since only numbers with the same 

exponent can be added. 

Floating-point number format in STEP 7 

Floating-point numbers in STEP 7 conform to the basic format, single width, 

described in the ANSI/IEEE standard 754-1985, IEEE Standard for Binary 

Floating-Point Arithmetic. They consist of the following components: 

• The sign S 

• The exponent e = E + bias, increased by a constant (bias = +127) 

• The fractional part of the mantissa m. 

The whole number part of the mantissa is not stored with the rest, because it is 

always equal to 1 within the valid number range. 

The three components together occupy one double word (32 bits): 

 

 

 

 

 

 

 

 

 

The following table shows the values of the individual bits in floating-point format. 

Component of the Floating- 

Point Number 

Bit Number 

Value 

Sign S 31 

Exponent e 30 2 to the power of 7 

... ... ... 



Mantissa m 22 2 to the power of -1 

... ... ... 




A5E00706944-01 A-35

Appendix 

Using the three components S, e, and m, the value of a number represented in this 

form is defined by the formula: 

Number = 1.m ∗ 2 to the power of (e - bias) 

Where: 

• e: 1 ≤ e ≤ 254 

• Bias: bias = 127. This means that an additional sign is not required for the 

exponent. 

• S: for a positive number, S = 0 and for a negative number, S = 1. 

Value Range of Floating-Point Numbers 

Using the floating-point format shown above, the following results: 

• The smallest floating-point number = 1.0 ∗ 2 to the power of (1-127) = 1.0 ∗ 2 

to the power of (-126) 

= 1.175 495E-38 and 

• The largest floating-point number = 2-2 to the power of (-23) ∗ 2 to the power of 

(254-127) = 2-2 to the power of (-23) ∗ 2 to the power of (+127) 

= 3.402 823E+38 

The number zero is represented with e = m = 0; e = 255 and m = 0 stands for 

"infinite." 

Format Range 1) 

Floating-point numbers according to the -3.402 823E+38 to -1.175 495E-38 

ANSI/IEEE standard 

and 0 and 

+1.175 495E-38 to +3.402 823E+38 

The following table shows the signal state of the bits in the status word for the 

results of instructions with floating-point numbers that do not lie within the valid 

range: 

Invalid Range for a Result CC1 CC0 OV OS 

-1.175494E-38 < result < -1.401298E-45 (negative number) 0 0 1 1 

underflow 

+1.401298E-45 < result < +1.175494E-38 (positive number) 

underflow 

0 0 1 1 

Result < -3.402823E+38 (negative number) overflow 0 1 1 1 

Result > 3.402823E+38 (positive number) overflow 1 0 1 1 

Not a valid floating-point number or invalid instruction (input 

value outside the valid value range) 

1 1 1 1 

Note when using mathematical operations: 

The result "Not a valid floating-point number" is obtained, for example, when you 

attempt to extract the square root from -2. You should therefore always evaluate 

the status bits first in math operations before continuing calculations based on the 

result. 


A-36 A5E00706944-01

Appendix 

Note when modifying variables: 

If the values for floating-point operations are stored in memory double words, for 

example, you can modify these values with any bit patterns. However, not every bit 

pattern is a valid number. 

Accuracy when Calculating Floating-Point Numbers 

! 

Caution 

Calculations involving a long series of values including very large and very small 

numbers can produce inaccurate results. 

The floating-point numbers in STEP 7 are accurate to 6 decimal places. You can 

therefore only specify a maximum of 6 decimal places when entering floating-point 

constants. 

Note 

The calculation accuracy of 6 decimal places means, for example, that the addition 

of number1 + number2 = number1 if number1 is greater than number2 ∗ 10 to the 

power of y, where y>6: 

100 000 000 + 1 = 100 000 000. 

Examples of Numbers in Floating-Point Format 

The following figure shows the floating-point format for the following decimal 

values: 

• 10.0 

• Pi (3.141593) 

• Square root of 2 (1.414214) 

The number 10.0 in the first example results from its floating-point format 

(hexadecimal representation: 4120 0000) as follows: 

e = 2 to the power of 7 + 2 to the power of 1 = 2 + 128 = 130 

m = 2 to the power of (-2) = 0.25 


A5E00706944-01 A-37

Appendix 

This results in: 

(1 + m) ∗ 2 to the power of (e - bias) = 1.25 ∗ 2 to the power of 3 = 10.0 

[1.25 ∗ 2 to the power of (130-127) = 1.25 ∗ 2 to the power of 3 = 10.0] 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A-38 A5E00706944-01

Appendix 

A.3.2.4 

Format of the Data Types WORD and DWORD in Binary Coded 

Decimal Numbers 

The binary-coded decimal (BCD) format represents a decimal number by using 

groups of binary digits (bits). One group of 4 bits represents one digit of a signed 

decimal number or the sign of the decimal number. The groups of 4 bits are 

combined to form a word (16 bits) or double word (32 bits). The four most 

significant bits indicate the sign of the number (1111 indicates minus and 0000 

indicates plus). Commands with BCD-coded addresses only evaluate the 

highest-value bit (15 in word, 31 in double word format). The following table shows 

the format and range for the two types of BCD numbers. 

Format 

Word 

(16 bits, three-digit BCD number with sign) 

Double word 

(32 bits, seven-digit BCD number with sign) 

Range 

-999 to +999 

-9 999 999 to +9 999 999 

The following figures provide an example of a binary coded decimal number in the 

following formats: 

• Word format 

 

 

 

 

 

• Double word format 

 

 

 

 

 

 

 


A5E00706944-01 A-39

Appendix 

A.3.2.5 

Format of the Data Type S5TIME (Time Duration) 

When you enter time duration using the S5TIME data type, your entries are stored 

in binary coded decimal format. The following figure shows the content of the time 

address with a time value of 127 and a time base of 1 s. 

 

 

 

 

 

 

When working with S5TIME, you enter a time value in the range of 0 to 999 and 

you indicate a time base (see the following table). The time base indicates the 

interval at which a timer decrements the time value by one unit until it reaches 0. 

Time base for S5TIME 

Time Base 

Binary Code for Time Base 

10 ms 00 

100 ms 01 

1 s 10 

10 s 11 

You can pre-load a time value using either of the following syntax formats: 

• L 1) W#16#wxyz 

- Where w = time base (that is, the time interval or resolution) 

- Where xyz = the time value in binary coded decimal format 

• L 1) S5T#aH_bbM_ccS_dddMS 

- Where a = hours, bb = minutes, cc = seconds, and dd = milliseconds 

- The time base is selected automatically and the value is rounded to the 

next lower number with that time base. 

The maximum time value that you can enter is 9,990 seconds, or 2H_46M_30S. 

1) 

= L only to be specified in STL programming 


A-40 A5E00706944-01

Appendix 

A.3.3 

Complex Data Types 

Complex data types define data groups that are larger than 32 bits or data groups 

consisting of other data types. STEP 7 permits the following complex data types: 

• DATE_AND_TIME 

• STRING 

• ARRAY 

• STRUCT 

• UDT (user-defined data types) 

• FBs and SFBs 

The following table describes the complex data types. You define structures and 

arrays either in the variable declaration of the logic block or in a data block. 

Data Type 

DATE_AND_TIME 

DT 

STRING 

ARRAY 

STRUCT 

UDT 

FB, SFB 

Description 

Defines an area with 64 bits (8 bytes). This data type saves in binary coded 

decimal format: 

Defines a group with a maximum of 254 characters (data type CHAR). The 

standard area reserved for a character string is 256 bytes long. This is the space 

required to save 254 characters and a header of 2 bytes. You can reduce the 

memory required for a string by defining the number of characters that will be 

stored in the character string (for example: string[9] 'Siemens'). 

Defines a multi-dimensional grouping of one data type (either elementary or 

complex). For example: "ARRAY [1..2,1..3] OF INT" defines an array in the format 

2 x 3 consisting of integers. You access the data stored in an array using the 

Index ("[2,2]"). You can define up to a maximum of 6 dimensions in one array. 

The index can be any integer (-32768 to 32767). 

Defines a grouping of any combination of data types. You can, for example, 

define an array of structures or a structure of structures and arrays. 

Simplifies the structuring of large quantities of data and entering data types when 

creating data blocks or declaring variables in the variable declaration. In STEP 7, 

you can combine complex and elementary data types to create your own 

"user-defined" data type. UDTs have their own name and can therefore be used 

more than once. 

You determine the structure of the assigned instance data block and allow the 

transfer of instance data for several FB calls in one instance DB. 

Structured data types are saved in accordance with word limits (WORD aligned). 


A5E00706944-01 A-41

Appendix 

A.3.3.1 

Format of the Data Type DATE_AND_TIME 

When you enter date and time using the DATE_AND_TIME data type (DT), your 

entries are stored in binary coded decimal format in 8 bytes. The 

DATE_AND_TIME data type has the following range: 

DT#1990-1-1-0:0:0.0 to DT#2089-12-31-23:59:59.999 

The following examples show the syntax for the date and time for Thursday, 

December 25, 1993, at 8:12 and 34,567 seconds in the morning. The following two 

formats are possible: 

• DATE_AND_TIME#1993-12-25-8:12:34.567 

• DT#1993-12-25-8:12:34.567 

The following special IEC (International Electrotechnical Commission) standard 

functions are available for working with the DATE_AND_TIME data type: 

• Convert date and time of day to the DATE_AND_TIME format 

FC3: D_TOD_DT 

• Extract the date from the DATE_AND_TIME format 

FC6: DT_DATE 

• Extract the day of the week from the DATE_AND_TIME format 

FC7: DT_DAY 

• Extract the time of day from the DATE_AND_TIME format 

FC8: DT_TOD 

The following table shows the contents of the bytes that contain the date and time 

information for the example Thursday, December 25, 1993, at 8:12 and 34,567 

seconds in the morning. 

Byte Contents Example 

0 Year B#16#93 

1 Month B#16#12 

2 Day B#16#25 

3 Hour B#16#08 

4 Minute B#16#12 

5 Second B#16#34 

6 Two most significant digits of MSEC B#16#56 

7 

(4MSB) 

Two least significant digits of MSEC 

B#16#7 

7 

(4LSB) 

Day of week 

1 = Sunday 

2 = Monday 

... 

7 = Saturday 

B#16#_5 


A-42 A5E00706944-01

Appendix 

The permitted range for the data type DATE_AND_TIME is: 

• min.: DT#1990-1-1-0:0:0.0 

• max.: DT#2089-12-31-23:59:59.999 

Possible Value Range 

BCD Code 

Year 1990 - 1999 

2000 - 2089 

90 - 99 

00 - 89 

Month 1 - 12 01 - 12 

Day 1 - 31 01 - 31 

Hour 00 - 23 00 - 23 

Minute 00 - 59 00 - 59 

Second 00 - 59 00 - 59 

Millisecond 0 - 999 000 - 999 

Day of week Sunday - Saturday 1 - 7 


A5E00706944-01 A-43

Appendix 

A.3.3.2 

Using Complex Data Types 

You can create new data types by combining the elementary and complex data 

types to create the following complex data types: 

• Array (data type ARRAY): an array combines a group of one data type to form 

a single unit. 

• Structure (data type STRUCT): a structure combines different data types to 

form a single unit. 

• Character string (data type STRING): a character string defines a 

one-dimensional array with a maximum of 254 characters (data type CHAR). A 

character string can only be transferred as a unit. The length of the character 

string must match the formal and actual parameter of the block. 

• Date and time (data type DATE_AND_TIME): the date and time data type 

stores the year, month, day, hours, minutes, seconds, milliseconds, and day of 

the week. 

The following figure shows how arrays and structures can structure data types in 

one area and save information. You define an array or a structure either in a DB or 

in the variable declaration of an FB, OB, or FC. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A-44 A5E00706944-01

Appendix 

A.3.3.3 

Using Arrays to Access Data 

Arrays 

An array combines a group of one data type (elementary or complex) to form a 

unit. You can create an array consisting of arrays. When you define an array, you 

must do the following: 

• Assign a name to the array. 

• Declare an array with the keyword ARRAY. 

• Specify the size of the array using an index. You specify the first and last 

number of the individual dimensions (maximum 6) in the array. You enter the 

index in square brackets with each dimension separated by a comma and the 

first and last number of the dimension by two periods. The following index 

defines, for example, a three-dimensional array: 

[1..5,-2..3,30..32] 

• You specify the data type of the data to be contained in the array. 

Example: 1 

The following figure shows an array with three integers. You access the data stored 

in an array using the index. The index is the number in square brackets. The index 

of the second integer, for example, is Op_temp[2]. 

An index can be any integer (-32768 to 32767) including negative values. The 

array in the following figure could also be defined as ARRAY [-1..1]. The index of 

the first integer would then be Op_temp[-1], the second would be Op_temp[0], and 

the third integer would then be Op_temp[1]. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 A-45

Appendix 

Example 2 

An array can also describe a multi-dimensional group of data types. The following 

figure shows a two-dimensional array of integers. 

Op_Temp = 

 

1,1 

1,2 

1,3 

2,1 

2,2 

2,3 

Integer 

Integer 

Integer 

Integer 

Integer 

Integer 

You access the data in a multi-dimensional array using the index. In this example, 

the first integer is Op_temp[1,1], the third is Op_temp[1,3], the fourth is 

Op_temp[2,1], and the sixth is Op_temp[2,3]. 

You can define up to a maximum of 6 dimensions (6 indexes) for an array. You 

could, for example, define the variable Op_temp as follows as a six-dimensional 

array: 

ARRAY [1..3,1..2,1..3,1..4,1..3,1..4] 

The index of the first element in this array is Op_temp[1,1,1,1,1,1]. The index of the 

last element Op_temp[3,2,3,4,3,4]. 

Creating Arrays 

You define arrays when you declare the data in a DB or in the variable declaration. 

When you declare the array, you specify the keyword (ARRAY) followed by the 

size in square brackets, as follows: 

[lower limit value..upper limit value] 

In a multi-dimensional array you also specify the additional upper and lower limit 

values and separate the individual dimensions with a comma. The following figure 

shows the declaration for creating an array of the format 2 x 3. 

 

 

 

 

 

 

 

 

 

 


A-46 A5E00706944-01

Appendix 

Entering Initial Values for an Array 

You can assign an initial value to every array element when you create arrays. 

STEP 7 provides two methods for entering initial values: 

• Entry of individual values: for each element of the array, you specify a value 

that is valid for the data type of the array. You specify the values in the order of 

the elements: [1,1]. Remember that the individual elements must be separated 

from each other by a comma. 

• Specifying a repetition factor: with sequential elements that have the same 

initial value, you can specify the number of elements (the repetition factor) and 

the initial value for these elements. The format for entering the repetition factor 

is x(y), where x is the repetition factor and y is the value to be repeated. 

If you use the array declared in the above figure, you can specify the initial value 

for all six elements as follows: 17, 23, -45, 556, 3342, 0. You could also set the 

initial value of all six elements to 10 by specifying 6(10). You could specify specific 

values for the first two elements and then set the remaining four elements to 0 by 

specifying the following: 17, 23, 4(0). 

Accessing Data in an Array 

You access data in an array via the index of the specific element in the array. The 

index is used with the symbolic name. 

Example: If the array declared in the above figure begins at the first byte of DB20 

(motor), you access the second element in the array with the following address: 

Motor.Heat_2x3[1,2]. 

Using Arrays as Parameters 

You can transfer arrays as parameters. If a parameter is declared in the variable 

declaration as ARRAY, you must transfer the entire array (and not individual 

elements). An element of an array can, however be assigned to a parameter when 

you call a block, providing the element of the array corresponds to the data type of 

the parameter. 

If you use arrays as parameters, the arrays do not need to have the same name 

(they do not even need a name). Both arrays (the formal parameter and the actual 

parameter) must however have the same structure. An array in the format 2 x 3 

consisting of integers, for example, can only be transferred as a parameter when 

the formal parameter of the block is defined as an array in the format 2 x 3 

consisting of integers and the actual parameter that is provided by the call 

operation is also an array in the format 2 x 3 consisting of integers. 


A5E00706944-01 A-47

Appendix 

A.3.3.4 

Using Structures to Access Data 

Structures 

A structure combines various data types (elementary and complex data types, 

including arrays and structures) to form one unit. You can group the data to suit 

your process control. You can therefore also transfer parameters as a data unit and 

not as single elements. The following figure illustrates a structure consisting of an 

integer, a byte, a character, a floating-point number, and a Boolean value. 

 

 

 

 

 

 

 

 

 

 

 

A structure can be nested to a maximum of 8 levels (for example, a structure 

consisting of structures containing arrays). 

Creating a Structure 

You define structures when you declare data within a DB or in the variable 

declaration of a logic block. 

The following figure illustrates the declaration of a structure (Stack_1) that consists 

of the following elements: an integer (for saving the amount), a byte (for saving the 

original data), a character (for saving the control code), a floating-point number (for 

saving the temperature), and a Boolean memory bit (for terminating the signal). 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A-48 A5E00706944-01

Appendix 

Assigning Initial Values for a Structure 

If you want to assign an initial value to every element of a structure, you specify a 

value that is valid for the data type and the name of the element. You can, for 

example, assign the following initial values (to the structure declared in the above 

figure): 

Amount = 100 

Original_data = B#(0) 

Control_code = 'C' 

Temperature = 120 

End = False 

Saving and Accessing Data in Structures 

You access the individual elements of a structure. You can use symbolic 

addresses (for example, Stack_1.Temperature). You can, however, specify the 

absolute address at which the element is located (example: if Stack_1 is located in 

DB20 starting at byte 0, the absolute address for amount is DB20.DBW0 and the 

address for temperature is DB20.DBD6). 

Using Structures as Parameters 

You can transfer structures as parameters. If a parameter is declared as STRUCT 

in the variable declaration, you must transfer a structure with the same 

components. An element of a structure can, however, also be assigned to a 

parameter when you call a block providing the element of the structure 

corresponds to the data type of the parameter. 

If you use structures as parameters, both structures (for the formal parameters and 

the actual parameters) must have the same components, in other words the same 

data types must be arranged in the same order. 


A5E00706944-01 A-49

Appendix 

A.3.3.5 

Using User-Defined Data Types to Access Data 

User-Defined Data Types 

User-defined data types (UDTs) can combine elementary and complex data types. 

You can assign a name to UDTs and use them more than once. The following 

figure illustrates the structure of a user-defined data type consisting of an integer, a 

byte, a character, a floating-point number, and a Boolean value. 

 

 

 

 

 

 

 

 

 

 

 

Instead of entering all the data types singly or as a structure, you only need to 

specify "UDT20" as the data type and STEP 7 automatically assigns the 

corresponding memory space. 

Creating a User-Defined Data Type 

You define UDTs with STEP 7. The following figure shows a UDT consisting of the 

following elements: an integer (for saving the amount), a byte (for saving the 

original data), a character (for saving the control code), a floating-point number (for 

saving the temperature), and a Boolean memory bit (for terminating the signal). 

You can assign a symbolic name to the UDT in the symbol table (for example, 

process data). 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Once you have created a UDT, you can use the UDT like a data type if, for 

example, you declare the data type UDT200 for a variable in a DB (or in the 

variable declaration of an FB). 

The following figure shows a DB with the variables process_data_1 with the data 

type UDT200. You only specify UDT200 and process_data_1. The arrays shown in 

italics are created when you compile the DB. 

 

 

 

 

 

 

 

 


A-50 A5E00706944-01

Appendix 

Assigning Initial Values for a User-Defined Data Type 

If you want to assign an initial value to every element of a user-defined data type, 

you specify a value that is valid for the data type and the name of the element. You 

can, for example, assign the following initial values (to the user-defined data type 

declared in the above figure): 

Amount = 100 

Original_data = B#16#0) 

Control_code = 'C' 

Temperature = 1.200000e+002 

End = False 

If you declare a variable as a UDT, the initial values of the variables are the values 

you specified when you created the UDT. 

Saving and Accessing Data in a User-Defined Data Type 

You access the individual elements of a UDT. You can use symbolic addresses (for 

example Stack_1.Temperature). You can, however specify the absolute address at 

which the element is located (example: if Stack_1 is located in DB20 starting at 

byte 0, the absolute address for amount is DB20.DBW0 and the address for 

temperature is DB20.DBD6). 

Using User-Defined Data Types as Parameters 

You can transfer variables of the data type UDT as parameters. If a parameter is 

declared as UDT in the variable declaration, you must transfer a UDT with the 

same structure. An element of a UDT can, however, also be assigned to a 

parameter when you call a block providing the element of the UDT corresponds to 

the data type of the parameter. 

Advantages of DBs with an Assigned UDT 

By using UDTs you have created once, you can generate a large number of data 

blocks with the same data structure. You can then use these data blocks to enter 

different actual values for specific tasks. 

If, for example, you structure a UDT for a formula (for example, for blending 

colors), you can assign this UDT to several DBs each containing different amounts. 

 

 

 

 

 

The structure of the data block is determined by the UDT assigned to it. 


A5E00706944-01 A-51

Appendix 

A.3.4 

Parameter Types 

In addition to elementary and complex data types, you can also define parameter 

types for formal parameters that are transferred between blocks. STEP 7 

recognizes the following parameter types: 

• TIMER or COUNTER: this specifies a particular timer or particular counter that 

will be used when the block is executed. If you supply a value to a formal 

parameter of the TIMER or COUNTER parameter type, the corresponding 

actual parameter must be a timer or a counter, in other words, you enter "T" or 

"C" followed by a positive integer. 

• BLOCK: specifies a particular block to be used as an input or output. The 

declaration of the parameter determines the block type to be used (FB, FC, DB 

etc.). If you supply values to a formal parameter of the BLOCK parameter type, 

specify a block address as the actual parameter. Example: "FC101" (when 

using absolute addressing) or "Valve" (with symbolic addressing). 

• POINTER: references the address of a variable. A pointer contains an address 

instead of a value. When you supply a value to a formal parameter of the 

parameter type POINTER, you specify an address as the actual parameter. In 

STEP 7, you can specify a pointer in the pointer format or simply as an address 

(for example, M 50.0). Example of a pointer format for addressing the data 

beginning at M 50.0: P#M50.0 

• ANY: this is used when the data type of the actual parameter is unknown or 

when any data type can be used. For more information about the ANY 

parameter type, refer to the sections "Format of the Parameter Type ANY" and 

"Using the Parameter Type ANY". 

A parameter type can also be used in a user-defined data type (UDT). For more 

information about UDTs, refer to the section "Using User-Defined Data Types to 

Access Data". 

Parameter Capacity Description 

TIMER 2 bytes Indicates a timer to be used by the program in the called logic 

block. 

Format: T1 

COUNTER 2 bytes Indicates a counter to be used by the program in the called 

logic block. 

Format: C10 

BLOCK_FB 

BLOCK_FC 

BLOCK_DB 

BLOCK_SDB 

2 bytes Indicates a block to be used by the program in the called logic 

block. 

Format: FC101 

DB42 

POINTER 6 bytes Identifies the address. 

Format: P#M50.0 

ANY 10 Bytes Is used when the data type of the current parameter is 

unknown. 

Format: 

P#M50.0 BYTE 10 ANY format for data types 

P#M100.0 WORD 5 

L#1COUNTER 10 

ANY format for 

parameter types 


A-52 A5E00706944-01

Appendix 

A.3.4.1 

Format of the Parameter Types BLOCK, COUNTER, TIMER 

STEP 7 stores the parameter types BLOCK, COUNTER, and TIMER as binary 

numbers in a word (32 bits). The following figure shows the format of these 

parameter types. 

 

 

 

The permitted number of blocks, timers, and counters is dependent on the type of 

your S7 CPU. You will find more information on the permitted number of timers and 

counters and on the maximum number of available blocks in the data sheets for 

your CPU in the "S7-300 Programmable Controller, Hardware and Installation 

Manual" or in the "S7-400, M7-400 Programmable Controllers, Hardware and 

Installation Manual." 

A.3.4.2 

Format of the Parameter Type POINTER 

The following figure shows the type of data that is stored in each byte. 

 

 

 

 

 

 

 

 

 

 

 

 

The parameter type POINTER stores the following information: 

• DB number (or 0 if the data are not stored in a DB) 

• Memory area in the CPU (the following table shows the hexadecimal codes of 

the memory areas for the parameter type POINTER) 

Hexadecimal Code Memory Area Description 

b#16#81 I Input area 

b#16#82 Q Output area 

b#16#83 M Bit memory area 

b#16#84 DB Data block 

b#16#85 DI Instance data block 

b#16#86 L Local data (L stack) 

b#16#87 V Previous local data 


A5E00706944-01 A-53

Appendix 

• Address of the data (in the format Byte.Bit) 

STEP 7 provides the pointer format: p#memory_area byte.bit_address. (If 

the formal parameter was declared as the parameter type POINTER, you 

only need to indicate the memory area and the address. STEP 7 

automatically reformats your entry into pointer format.) The following 

examples show how you enter the parameter type POINTER for the data 

that start at M50.0: 

• P#M50.0 

• M50.0 (if the formal parameter was declared as POINTER). 

A.3.4.3 

Using the Parameter Type POINTER 

A pointer is used to point to an address. The advantage of this type of addressing 

is that you can modify the address of the statement dynamically during program 

processing. 

Pointer for Memory-Indirect Addressing 

Program statements that work with memory-indirect addressing are made up of an 

instruction, an address identifier, and an offset (the offset must be given in square 

brackets). 

Example of a pointer in double word format: 

L P#8.7 Load the value of the pointer into accumulator 1. 

T MD2 Transfer the pointer to MD2. 

A I [MD2] Query the signal state at input bit I 8.7 and 

= Q [MD2] assign the signal state to output bit Q 8.7. 

Pointer for Area-Internal and Area-Crossing Addressing 

The program statements that work with these types of addressing are comprised of 

an instruction and the following parts: address identifier, address register identifier, 

offset. 

The address register (AR1/2) and the offset must be specified together in square 

brackets. 

Example for Area-Internal Addressing 

The pointer contains no indication of a memory area: 

L P#8.7 Load the value of the pointer into accumulator 1. 

LAR1 

Load the pointer from accumulator 1 into AR1. 

A I [AR1, P#0.0] Query the signal state at input bit I 8.7 and 

= Q [AR1, P#1.1] assign the signal state to output bit Q 10.0. 


A-54 A5E00706944-01

Appendix 

The offset 0.0 has no influence. Output 10.0 is calculated from 8.7 (AR1) plus the 

offset 1.1. The result is 10.0 and not 9.8, see pointer format. 

Example for Area-Crossing Addressing 

In area-crossing addressing the memory area is indicated in the pointer (in the 

example I and Q). 

L P# I8.7 Load the value of the pointer and the area identification in 

accumulator 1. 

LAR1 

Load memory area I and the address 8.7 into AR1. 

L P# Q8.7 Load the value of the pointer and the area identification in 

accumulator 1. 

LAR2 

Load memory area Q and the address 8.7 into AR2. 

A [AR1, P#0.0] Query the signal state at input bit I 8.7 and 

= [AR2, P#1.1] assign the signal state to output bit Q 10.0. 

The offset 0.0 has no influence. Output 10.0 is calculated from 8.7 (AR2) plus the 

offset 1.1. The result is 10.0 and not 9.8, see pointer format. 

A.3.4.4 

Block for Changing the Pointer 

Using the sample block FC3 "Routing Pointers" it is possible to change the bit or 

byte address of a pointer. The pointer to be changed is transferred to the variable 

"pointer" when the FC is called (area-internal and area-crossing pointers in double 

word format can be used). 

With the parameter "Bit-Byte" you can change the bit or byte address of the pointer 

(0: bit address, 1: byte address). The variable "Inc_Value" (in integer format) 

specifies the number that should be added to or subtracted from the address 

contents. You can also specify negative numbers to decrement the address. 

With a bit address change, there is a carry over to the byte address (also when 

decrementing), for example: 

• P#M 5.3, Bit_Byte = 0, Inc_Value = 6 => P#M 6.1 or 

• P#M 5.3, Bit_Byte = 0, Inc_Value = -6 => P#M 4.5. 

The area information of the pointer is not influenced by the function. 

The FC intercepts an overflow/underflow of the pointer. In this case the pointer is 

not changed and the output variable "RET_VAL" (error handling possible) is set to 

"1" (until the next correct processing of FC3). This is the case where: 

• 1. Bit address is selected and Inc_Value >7, or

Appendix 

Sample Block in STL to Change the Pointer 

FUNCTION FC 3: BOOL 

TITLE =Routing Pointers 

//FC3 can be used to change pointers. 

AUTHOR : AUT1CS1 

FAMILY : INDADDR 

NAME : ADDRPOINT 

VERSION : 0.0 

VAR_INPUT 

Bit_Byte : BOOL ; //0: Bit address, 1: byte address 

Inc_Value : INT ; //Increment (if value neg. => decrement/if 

value pos. => increment) 

END_VAR 

VAR_IN_OUT 

Pointer : DWORD ; //Pointer to be changed 

END_VAR 

VAR_TEMP 

Inc_Value1 : INT ; //Interim value increment 

Pointer1 : DWORD ; //Interim value pointer 

Int_Value : DWORD ; //Auxiliary variable 

END_VAR 

BEGIN 

NETWORK 

TITLE = 

//The block intercepts changes that change the area information of 

//the pointer or that lead to "negative" pointers automatically. 

SET ; //Set RLO to 1 and 

R #RET_VAL; //reset overflow 

L #Pointer; //Supply value to temporary 

T #Pointer1; //interim value pointer 

L #Inc_Value; //Supply value of temporary 

T #Inc_Value1; //interim value increment 

A #Bit_Byte; //If =1, byte address instruction 

JC Byte; //Jump to byte address calculation 

L 7; //If value of increment > 7, 

L #Inc_Value1; 

Appendix 

JC neg; //then jump to bit address subtraction 

L #Pointer1; //Load pointer address information 

L #Inc_Value1; //and add the increment 

+D ; 

JU test; //Jump to test for negative result 

neg: L #Pointer1; //Load pointer address information 

L #Inc_Value1; //Load the increment 

NEGI ; //Negate the negative value, 

-D ; //subtract the value 

JU test; //and jump to test 

Byte: L 0; //Start of byte address change 

L #Inc_Value1; //If increment >=0, then 

Appendix 

A.3.4.5 

Format of the Parameter Type ANY 

STEP 7 stores the parameter type ANY in 10 bytes. When constructing a 

parameter of the type ANY, you must ensure that all 10 bytes are occupied 

because the called block evaluates the whole contents of the parameter. If, for 

example, you specify a DB number in byte 4, you must also explicitly specify the 

memory area in byte 6. 

STEP 7 manages the data of elementary and complex data types differently from 

the data for parameter types. 

ANY Format for Data Types 

For elementary and complex data types STEP 7 stores the following data: 

• Data types 

• Repetition factor 

• DB number 

• Memory area in which the information is stored 

• Start address of the data 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The repetition factor identifies a quantity of the indicated data type to be transferred 

by the parameter type ANY. This means you can specify a data area and also use 

arrays and structures in conjunction with the parameter type ANY. STEP 7 

identifies arrays and structures as a number (with the help of the repetition factor) 

of data types. If, for example, 10 words are to be transferred, the value 10 must be 

entered for the repetition factor and the value 04 must be entered for the data type. 

The address is stored in the format Byte.Bit where the byte address is stored in bits 

0 to 2 of byte 7, in bits 0 to 7 of byte 8, and in bits 3 to 7 of byte 9. The bit address 

is stored in bits 0 to 2 of byte 9. 

With a null pointer of the type NIL all bytes from byte 1 are assigned 0. 


A-58 A5E00706944-01

Appendix 

The following tables show the coding of the data types or of the memory areas for 

the parameter type ANY. 

Coding of the Data Types 

Hexadecimal Code Data Type Description 

b#16#00 NIL Null pointer 

b#16#01 BOOL Bits 

b#16#02 BYTE Bytes (8 bits) 

b#16#03 CHAR Characters (8 bits) 

b#16#04 WORD Words (16 bits) 

b#16#05 INT Integers (16 bits) 

B#16#06 DWORD Words (32 bits) 

b#16#07 DINT Double integers (32 bits) 

b#16#08 REAL Floating-point numbers (32 bits) 

b#16#09 DATE Date 

b#16#0A TIME_OF_DAY (TOD) Time of day 

b#16#0B TIME Time 

b#16#0C S5TIME Data type S5TIME 

b#16#0E 

DATE_AND_TIME (DT) Date and time (64 bits) 

b#16#13 STRING String 

Coding of the Memory Areas 

HexadecimalCode Area Description 

b#16#81 I Input area 

b#16#82 Q Output area 

b#16#83 M Bit memory area 

b#16#84 DB Data block 

b#16#85 DI Instance data block 

b#16#86 L Local data (L stack) 

b#16#87 V Previous local data 


A5E00706944-01 A-59

Appendix 

ANY Format for Parameter Types 

For parameter types STEP 7 stores the data type and the address of the 

parameters. The repetition factor is always 1. Bytes 4, 5, and 7 are always 0. Bytes 

8 and 9 indicate the number of the timer, counter, or block. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The following table shows the coding of the data types for the parameter type ANY 

for parameter types. 

Hexadecimal Code Data Type Description 

b#16#17 BLOCK_FB FB number 

b#16#18 BLOCK_FC FC number 

b#16#19 BLOCK_DB DB number 

b#16#1A BLOCK_SDB SDB number 

b#16#1C COUNTER Counter number 

b#16#1D TIMER Timer number 


A-60 A5E00706944-01

Appendix 

A.3.4.6 

Using the Parameter Type ANY 

You can define formal parameters for a block that are suitable for actual 

parameters of any data type. This is particularly useful when the data type of the 

actual parameter that is provided when the block is called is unknown or can vary 

(and when any data type is permitted). In the variable declaration of the block, you 

declare the parameter as data type ANY. You can then assign an actual parameter 

of any data type in STEP 7. 

STEP 7 assigns 80 bits of memory for a variable of the ANY data type. If you 

assign an actual parameter to this formal parameter, STEP 7 codes the start 

address, the data type, and the length of the actual parameter in the 80 bits. The 

called block analyzes the 80 bits of data saved for the ANY parameter and obtains 

the information required for further processing. 

Assigning an Actual Parameter to an ANY Parameter 

If you declare the data type ANY for a parameter, you can assign an actual 

parameter of any data type to the formal parameter. In STEP 7, you can assign the 

following data types as actual parameters: 

• Elementary data types: you specify the absolute address or the symbolic name 

of the actual parameter. 

• Complex data types: you specify the symbolic name of the data with a complex 

data type (for example, arrays and structures). 

• Timers, counters, and blocks: you specify the number (for example, T1, C20, or 

FB6). 

• The following figure shows how data are transferred to an FC with parameters 

of the ANY data type. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 A-61

Appendix 

In this example, FC100 has three parameters (in_par1, in_par2, and in_par3) 

declared as the ANY data type. 

• When FB10 calls FC100, FB10 transfers an integer (the static variable speed), 

a word (MW100), and a double word to DB10 (DB10.DBD40). 

• When FB11 calls FC100, FB11 transfers an array of real numbers (the 

temporary variable "Thermo"), a Boolean value (M 1.3), and a timer (T2). 

Specifying a Data Area for an ANY Parameter 

You can assign not only individual addresses (for example, MW100) to an ANY 

parameter but you can also specify a data area. If you want to assign a data area 

as the actual parameter, use the following format of a constant to specify the 

amount of data to be transferred: 

p# Area ID Byte.Bit Data Type Repetition Factor 

For the data type element, you can specify all elementary data types and the data 

type DATE_AND_TIME in the format for constants. If the data type is not BOOL, 

the bit address of 0 (x.0) must be specified. The following table illustrates examples 

of the format for specifying memory areas to be transferred to an ANY parameter. 

Actual Parameter 

Description 

p# M 50.0 BYTE 10 Specifies 10 bytes in the byte memory area: 

MB50 to MB59. 

p# DB10.DBX5.0 S5TIME 3 Specifies 3 units of data of the data type S5TIME, that are 

located in DB10: 

DB byte 5 to DB byte 10. 

p# Q 10.0 BOOL 4 Specifies 4 bits in the output area: 

Q 10.0 to Q 10.3. 


A-62 A5E00706944-01

Appendix 

Example for Using the Parameter Type ANY 

The following example shows how you can copy a memory area of 10 bytes using 

the parameter type ANY and the system function SFC20 BLKMOV. 

STL 

FUNCTION FC10: VOID 

VAR_TEMP 

Source : ANY; 

Target : ANY; 

END_VAR 

BEGIN 

LAR1 P#Source; 

L B#16#10; 

T LB[AR1,P#0.0]; 

L B#16#02; 

T LB[AR1,P#1.0]; 

L 10; 

T LW[AR1,P#2.0]; 

L 22; 

T LW[AR1,P#4.0]; 

L P#DBX11.0; 

T LD[AR1,P#6.0]; 

Explanation 

Load the start address of the ANY pointer in AR1. 

Load the syntax ID and 

transfer it to the ANY pointer. 

Load data type Byte and 


Load 10 bytes and 

transfer them to the ANY pointer. 

Source is DB22, DBB11 

LAR1 

P#Target; 

Load the start address of the ANY pointer in AR1. 

L B#16#10; 

T LB[AR1,P#0.0]; 

L B#16#02; 

T LB[AR1,P#1.0]; 

L 10; 

T LW[AR1,P#2.0]; 

L 33; 

T LW[AR1,P#4.0]; 

L P#DBX202.0; 

T LD[AR1,P#6.0]; 

CALL SFC 20 ( 

SRCBLK := Source, 

RET_VAL := MW 12, 

DSTBLK := Target 

); 

END_FUNCTION 

Load the syntax ID and 


Load data type Byte and 


Load 10 bytes and 

transfer them to the ANY pointer. 

Target is DB33, DBB202 

Call the system function BLKMOV 

Evaluate the BR bit and MW12 


A5E00706944-01 A-63

Appendix 

A.3.4.7 

Assigning Data Types to Local Data of Logic Blocks 

With STEP 7, the data types (elementary and complex data types and parameter 

types) that can be assigned to the local data of a block in the variable declaration 

are restricted. 

Valid Data Types for the Local Data of an OB 

Declaration 

Type 

The following table illustrates the restrictions (-) for declaring local data for an OB. 

Since you cannot call an OB, an OB cannot have parameters (input, output, or 

in/out). Since an OB does not have an instance DB, you cannot declare any static 

variables for an OB. The data types of the temporary variables of an OB can be 

elementary or complex data types and the data type ANY. 

The valid assignments are shown by the • symbol. 

Elementary 

Data Types 

Complex 

Data Types 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

TIMER COUNTER BLOCK POINTER ANY 

Input — — — — — — — 

Output — — — — — — — 

In/out — — — — — — — 

Static — — — — — — — 

Temporary •(1) •(1) — — — — •(1) 

(1) 

Located in the L stack of the OB. 

Valid Data Types for the Local Data of an FB 

Declaration 

Type 

The following table illustrates the restrictions (-) for declaring local data for an FB. 

Due to the instance DB, there are less restrictions when declaring local data for an 

FB. When declaring input parameters there are no restrictions whatsoever; for an 

output parameter you cannot declare any parameter types, and for in/out 

parameters only the parameter types POINTER and ANY are permitted. You can 

declare temporary variables as the ANY data type. All other parameter types are 

illegal. 


Elementary 

Data Types 

Complex 

Data Types 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 


Input • • • • • • • 

Output • • — — — — — 

In/out • •(1)(3) — — — • • 

Static • • — — — — — 

Temporary •(2) •(2) — — — — •(2) 

1 

2 

3 

Stored as a reference (48-bit pointer) in the instance data block. 

Located in the L stack of the FB. 

STRINGS can be defined in the default length only. 


A-64 A5E00706944-01

Appendix 

Valid Data Types for the Local Data of an FC 

The following table illustrates the restrictions (-) for declaring local data for an FC. 

Since an FC does not have an instance DB, it also has no static variables. For 

input, output, and in/out parameters of an FC, only the parameter types POINTER 

and ANY are permitted. You can also declare temporary variables of the ANY 

parameter type. 


Declaration 

Type 

Elementary 

Data Types 

Complex 

Data Types 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 


Input • •(2) • • • • • 

Output • •(2) — — — • • 

In/out • •(2) — — — • • 

Temporary •(1) •(1) — — — — •(1) 

1 

2 

Located in the L stack of the FC. 

STRINGS can be defined in the default length only. 


A5E00706944-01 A-65

Appendix 

A.3.4.8 

Permitted Data Types when Transferring Parameters 

Rules for Transferring Parameters Between Blocks 

When you assign actual parameters to formal parameters, you can specify either 

an absolute address, a symbolic name, or a constant. STEP 7 restricts the valid 

assignments for the various parameters. Output and in/out parameters, for 

example, cannot be assigned a constant value (since the purpose of an output or 

an in/out parameter is to change its value). These restrictions apply particularly to 

parameters with complex data types to which neither an absolute address nor a 

constant can be assigned. 

The following tables illustrate the restrictions (-) involving the data types of actual 

parameters that are assigned to formal parameters. 


Declaration 

Type 

Absolute 

Address 

Elementary Data Types 

Symbolic Name 

(in the Symbol Table) 

Temporary Local 

Symbol 

Constant 

Input • • • • 

Output • • • — 

In/out • • • — 

Declaration 

Type 

Absolute 

Address 

Complex Data Types 

Symbolic Name of the DB 

Element 

(in the Symbol Table) 

Temporary Local 

Symbol 

Constant 

Input — • • — 

Output — • • — 

In/out — • • — 


A-66 A5E00706944-01

Appendix 

Valid Data Types for the Call of a Function by a Function 

You can assign the formal parameters of a calling FC to the formal parameters of a 

called FC. The following figure illustrates the formal parameters of FC10 that are 

assigned as actual parameters to the formal parameters of FC12. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

STEP 7 restricts the assignment of formal parameters of an FC as actual 

parameters for the formal parameters of a different FC. You cannot, for example, 

assign parameters with complex data types or a parameter type as the actual 

parameter. 

The following table shows the permitted data types (•) when one FC calls another 

FC. 

Declaration Type Elementary 

Data Types 

Complex 

Data 

Types 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 


Parameter 

Type 

Input → Input • — — — — — — 

Inpu → Output — — — — — — — 

Input → In/out — — — — — — — 

Output → Input — — — — — — — 

Output → Output • — — — — — — 

Output → In/out — — — — — — — 

In/out → Input • — — — — — — 

In/out → Output • — — — — — — 

In/out → In/out • — — — — — — 


A5E00706944-01 A-67

Appendix 

Valid Data Types for the Call of a Function by a Function Block 

You can assign the formal parameters of a calling FB to the formal parameters of a 

called FC. The following figure illustrates the formal parameters of FB10 that are 

assigned as actual parameters to the formal parameters of FC12. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

STEP 7 restricts the assignment of the formal parameters of an FB to the formal 

parameters of an FC. You cannot, for example, assign parameters of the 

parameter type as actual parameters. The following table shows the permitted data 

types (•) when an FB calls an FC. 

Declaration 

Type 

Elementary 

Data Types 

Complex 

Data 

Types 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 


Input → Input • • — — — — — 

Input → Output — — — — — — — 

Input → In/out — — — — — — — 

Output → Input — — — — — — — 

Output → Output • • — — — — — 

Output → In/out — — — — — — — 

In/out → Input • — — — — — — 

In/out → Output • — — — — — — 

In/out → In/out • — — — — — — 


A-68 A5E00706944-01

Appendix 

Valid Data Types for the Call of a Function Block by a Function 

You can assign the formal parameters of a calling FC to the formal parameters of a 

called FB. The following figure illustrates the formal parameters of FC10 that are 

assigned as actual parameters to the formal parameters of FB12. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

STEP 7 restricts the assignment of formal parameters of an FC to the formal 

parameters an FB. You cannot, for example, assign parameters with a complex 

data type as actual parameters. You can, however, assign input parameters of the 

parameter types TIMER, COUNTER, or BLOCK to the input parameters of the 

called FB. 

The following table shows the permitted data types (•) when an FC calls an FB. 

Declaration 

Type 

Elementary 

Data Types 

Complex 

Data 

Types 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 


Input → Input • — • • • — — 

Input → Output — — — — — — — 

Input → In/out — — — — — — — 

Output → Input — — — — — — — 

Output → Output • — — — — — — 

Output → In/out — — — — — — — 

In/out → Input • — — — — — — 

In/out → Output • — — — — — — 

In/out → In/out • — — — — — — 


A5E00706944-01 A-69

Appendix 

Valid Data Types for the Call of a Function Block by a Function Block 

You can assign the formal parameters of a calling FB to the formal parameters of a 

called FB. The following figure illustrates the formal parameters of FB10 that are 

assigned as actual parameters to the formal parameters of FB12. 

Function Block (FC) Call Function Block (FC) 

FB10 with DB10 

Variable declaration 

Param_1 Input 

Param_2 Output 

Param_3 In/out 

FB12 with DB11 

Variable declaration 

A_Param Input 

B_Param Output 

C_Param In/out 

Call FB12,DB11 

A_Param := Param_1 

B_Param := Param_2 

C_Param := Param_3 

STEP 7 restricts the assignment of the formal parameters of an FB to the formal 

parameters of another FB. You cannot, for example, assign input and output 

parameters with complex data types as the actual parameters for the input and 

output parameters of a called FB. You can, however, assign input parameters of 

the parameter types TIMER, COUNTER, or BLOCK to the input parameters of the 

called FB. 

The following table shows the permitted data types (•) when an FB calls another 

FB. 

Declaration 

Type 

Elementary 

Data Types 

Complex 

Data 

Types 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 

Parameter 

Type 


Input → Input • • • • • — — 

Input → Output — — — — — — — 

Input → In/out — — — — — — — 

Output → Input — — — — — — — 

Output → Output • • — — — — — 

Output → In/out — — — — — — — 

In/out → Input • — — — — — — 

In/out → Output • — — — — — — 

In/out → In/out • — — — — — — 


A-70 A5E00706944-01

Appendix 

A.3.4.9 

Transferring to IN_OUT Parameters of a Function Block 

When complex data types are transferred to IN_OUT parameters of a function 

block (FB) the address of the variable is transferred (call by reference). 

When elementary data types are transferred to IN_OUT parameters of a function 

block the values are copied into the instance data block before the function block is 

started and copied out of the instance data block after the function block is ended. 

This means IN_OUT variables of elementary data type can be initialized with a 

value. 

It is not possible, however, to specify a constant in place of an IN_OUT variable as 

the actual parameter in a call because a constant cannot be written to. 

Variables of the data type STRUCT or ARRAY cannot be initialized because only 

one address is in the instance data block in this case. 


A5E00706944-01 A-71

Appendix 

A.4 Working with Older Projects 

A.4.1 

Converting Version 1 Projects 

You can re-use projects you created with version 1 of STEP 7. To do this, you have 

to convert the version 1 projects to version 2 projects. 

The following components of a version 1 project are retained: 

• Project structure with programs 

• Blocks 

• STL source files 

• Symbol table 

The configuration of the hardware is not converted. You can copy the program 

components contained in the project to other projects. You can also add a station 

to the new project and configure and assign parameters to it. 

Once you have converted to version 2 you can decide in a dialog box whether you 

now want to convert this version 2 project to a project in your current STEP 7 

version. 

Note 

The individual blocks stay as version 1 blocks as regards their properties. The 

code generated in version 1 is not changed and the blocks cannot therefore be 

used in conjunction with multiple instances. 

If you want to declare multiple instances in the converted blocks, generate STL 

source files from the converted blocks first using the "LAD/STL/FBD: Programming 

Blocks" application and then compile them back into blocks. 

Programming multiple instances is a new feature of STEP 7 version 2 used to 

create function blocks (FB). If you want to continue using function blocks created 

with version 1 in the same way in a version 2 project, you do not need to convert 

them. 

Procedure 

To convert version 1 projects, proceed as follows: 

1. Select the menu command File > Open Version 1 Project. 

2. In the dialog box which appears, select the version 1 project which you want to 

use in version 2. You recognize a version 1 project by its extension *.s7a. 

3. Then, in the next dialog box, enter the name of the new project to which you 

want the version 1 project to be converted. 


A-72 A5E00706944-01

Appendix 

A.4.2 

Converting Version 2 Projects 

In STEP 7 you can also open version 2 projects using the menu command File > 

Open. 

Version 2 projects/libraries can be converted (migrated) to your current STEP 7 

version using the menu command File > Save As and the option "Rearrange 

before saving." The project is then saved as a project with the current STEP 7 

version. 

You can edit projects and libraries from older STEP 7 versions retaining their 

format and save them by selecting the older STEP 7 version as the file type in the 

"Save Project As" dialog box. For example, to edit the objects with STEP 7 version 

2.1, select "Project 2.x" or "Library 2.x" here (it is not possible to save as Version 2 

as from Version 5.1 on. Also refer to Editing Version 2 projects and libraries). 

Designation of the File Type 

File type of the current 

version 

File type of the older 

version 

STEP 7 V3 

Project3.x 

Library3.x 

Project2.x 

Library2.x 

From STEP 7 V4 

Project 

Library 

Project2.x 

Library2.x 

This means you only have access to the scope of functions of the older STEP 7 

version. You can, however, still continue to manage the projects and libraries with 

the older STEP 7 version. 

Note 

The upgrade from version 3 to versions 4 and higher only involves a change in name: the 

format has remained identical. Therefore there is no file type "Project3.x" in STEP 7 V4. 

Procedure 

To convert version 2 projects to the format of the current STEP 7 version, proceed 

as follows: 

1. Execute the "Save As" command in the File menu with the "Rearrange before 

saving" option for the project. 

2. Select the file type "Project" in the "Save Project As" dialog box and click the 

"Save" button. 

To convert version 2 projects to the current STEP 7 version while retaining their 

format, proceed as follows: 

1. Execute step 1 above if necessary. 

2. Select the file type of the older STEP 7 version in the "Save Project As" dialog 

box and click the "Save" button. 


A5E00706944-01 A-73

Appendix 

A.4.3 

Notes on STEP 7 V.2.1 Projects with GD Communication 

• If you want to convert a project with global data from STEP 7 V2.1 to 

STEP 7 V5, you must first open the GD table with STEP 7 V5.0 in the 

STEP 7 V2.1 project. The communication data configured previously are 

automatically converted into the new structure via GD communication. 

• When you archive STEP 7 V2.1 projects, older programs (ARJ, PKZIP...) may 

issue an error message if the project contains files with names which are more 

than eight characters in length. This message also appears if the MPI network 

in the STEP 7 V2.1 project was edited with an ID which is more than 8 

characters in length. In STEP 7 V2.1 projects with global data, edit a name for 

the MPI network which is a maximum of eight characters in length before you 

start to configure global data communication for the first time. 

• If you want to rename a STEP 7 V2.1 project, you must reassign the headings 

of the columns (CPUs) in the GD table by re-selecting the appropriate CPU. If 

you restore the old project name, the assignments are displayed once more. 

A.4.4 

DP-Slaves with Missing or Faulty GSD Files 

If you process older station configurations with STEP 7 Version 5.1, it is possible in 

rare cases that the GSD file of a DP slave is missing or cannot be not compiled (for 

example, due to syntax errors in the GSD file). 

In this case STEP 7 generates a "dummy" slave which represents the configured 

slave, for example after a station download to the programming device or after an 

older project has been opened and processed further. This "dummy" slave can only 

be processed to a limited extent. You cannot change the slave structure (DP 

identifiers) and the slave parameters. However, renewed downloading to the 

station is possible. The original configuration of the slave is retained. The complete 

DP slave can also be deleted. 

Reconfiguring and Assigning Parameters to the DP Slave 

If you wish to reconfigure or reassign parameters to the DP slave, you have to 

request an up-to-date GSD file for this DP slave from the manufacturer and make it 

available by using the menu command Options > Install GSD Files. 

After the correct GSD file has been installed, it is used to represent the DP slave. 

The DP slave contains its data and can be processed again completely. 


A-74 A5E00706944-01

Appendix 

A.5 Sample Programs 

A.5.1 

Sample Projects and Sample Programs 

The STEP 7 installation CD contains a number of sample projects that are listed 

below. You will find the sample projects in the "open" dialog of the SIMATIC 

Manager ("Sample Projects" tab). Other sample projects may also be added when 

optional packages are installed. For information on these sample projects, refer to 

the documentation for the optional packages. 

Examples and Sample Projects 

"ZEn01_01_STEP7_*" to "ZEn01_06_STEP7_*" 

projects (getting started and exercises) 

"ZEn01_11_STEP7_DezP" project (sample 

PROFIBUS DP configuration) 

"ZEn01_08_STEP7_Blending" project (industrial 

blending process) 

"ZEn01_09_STEP7_Zebra" project (traffic signal 

control at a zebra crossing/crosswalk) 

"Zen01_10_STEP7_COM_SFB" project (data 

exchange between two S7-400 CPUs) 

"ZXX01_14_HSystem_S7400H project (starting 

project for fault-tolerant systems) 

"ZXX01_15_HSystem_RED_IO project (starting 

project for fault-tolerant systems with redundant 

I/O devices) 

"Zen01_11_STEP7_COM_SFC1" and 

"Zen01_12_STEP7_COM_SFC2" project (data 

exchange using communication SFCs for nonconfigured 

connections) 

Project "ZEn01_13_STEP7_PID-Temp" 

(Example for temperature controllers FB 58 and 

FB 59) 

Example of handling time-of-day interrupts 

Example of handling time-delay interrupts 

Example of masking and unmasking 

synchronous errors 

Example of disabling and enabling interrupts and 

asynchronous errors 

Example of the delayed processing of interrupts 

and asynchronous errors 

Included on 

CD 

Described in 

this 

Documentation 

• Separate 

Manual 

• - - 

• • - 

• • 

• • 

• 

• 

Separate 

manual 

Separate 

manual 

• • 

• • 

• 

• 

• 

• 

• 

Description in 

OB1 

• 

• 

• 

The emphasis of the examples is not on teaching a particular programming style or 

the specialist knowledge needed to control a particular process. The examples are 

simply intended to illustrate the steps that must be followed to design a program. 


A5E00706944-01 A-75

Appendix 

Deleting and Installing the Supplied Sample Projects 

The supplied sample projects can be deleted in the SIMATIC Manager and then 

reinstalled. To install the sample projects, you must start the STEP 7 V5.0 setup 

program. The sample projects can be installed selectively at a later date. Copies of 

the supplied sample projects and self-created sample projects made using the 

menu command "Save As" can only be saved as user projects. 

Note 

When STEP 7 is installed, the supplied sample projects are copied, unless 

otherwise specified. If you have edited the supplied sample projects, these 

modified projects are overwritten with the originals when STEP 7 is reinstalled. 

For this reason, you should copy the supplied sample projects before making any 

changes and then only edit the copies. 


A-76 A5E00706944-01

Appendix 

A.5.2 

Sample Program for an Industrial Blending Process 

The sample program is makes use of information that you have already read in part 

1 of the manual about controlling an industrial blending process. 

Task 

Two ingredients (ingredient A and ingredient B) are mixed together in a mixing tank 

by an agitator. The finished product is drained from the tank through a drain valve. 

The following figure shows a diagram of the sample process. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Describing the Parts of a Process 

Part 1 of the manual included a description of how you divide up the sample 

process into functional areas and individual tasks. The individual areas are 

described below. 


A5E00706944-01 A-77

Appendix 

The area for ingredients A and B: 

• The pipes for each of the ingredients are equipped with an inlet and a feed 

valve and feed pump. 

• The inlet pipes also have flow sensors. 

• Turning on the feed pumps must be interlocked when the tank level sensor 

indicates that the tank is full. 

• The activation of the feed pumps must be interlocked when the drain valve is 

open. 

• The inlet and feed valves must be opened at the earliest 1 second after starting 

the feed pump. 

• The valves must be closed immediately after the feed pumps stop (signal from 

the flow sensor) to prevent ingredients leaking from the pump. 

• The activation of the feed pumps is combined with a time monitoring function, 

in other words, within 7 seconds after the pumps start, the flow sensor must 

report a flow. 

• The feed pumps must be turned off as quickly as possible if the flow sensor no 

longer signals a flow while the feed pumps are running. 

• The number of times that the feed pumps are started must be counted 

(maintenance interval). 

Mixing tank area: 

• The activation of the agitator motor must be interlocked when the tank level 

sensor indicates "level below minimum" or the drain valve is open. 

• The agitator motor sends a response signal after reaching the rated speed. If 

this signal is not received within 10 seconds after the motor is activated, the 

motor must be turned off. 

• The number of times that the agitator motor starts must be counted 

(maintenance interval). 

• Three sensors must be installed in the mixing tank: 

- Tank full: a normally closed contact. When the maximum tank level is 

reached, the contact is opened. 

- Level in tank above minimum: a normally open contact. If the minimum 

level is reached, the contact is closed. 

- Tank not empty: a normally open contact. If the tank is not empty, the 

contact is closed. 

Drain area: 

• Drainage of the tank is controlled by a solenoid valve. 

• The solenoid valve is controlled by the operator, but must be closed again at 

the latest when the "tank empty" signal is generated. 

• Opening the drain valve is interlocked when 

- the agitator motor is running 

- the tank is empty 


A-78 A5E00706944-01

Appendix 

Operator Station 

To allow an operator to start, stop, and monitor the process, an operator station is 

also required. The operator station is equipped with the following: 

• Switches for controlling the most important stages of the process. Using the 

"reset maintenance display" switch, you can turn off the maintenance display 

lamps for the motors due for maintenance and reset the corresponding 

counters for the maintenance interval to 0. 

• Display lamps to indicate the status of the process. 

• The emergency stop switch. 

A.5.2.1 

Defining Logic Blocks 

You structure the program by distributing the user program in various blocks and 

by establishing a hierarchy for block calls. 

Hierarchy of the Block Calls 

The following figure shows the hierarchy of the blocks to be called in the structured 

program. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 A-79

Appendix 

• OB1: The interface to the operating system of the CPU and contains the main 

program. In OB1 the blocks FB1 and FC1 are called and the specific 

parameters required to control the process are transferred. 

• FB1: The feed pump for ingredient A, the feed pump for ingredient B and the 

agitator motor can be controlled by a single function block because the 

requirements (on, off, count applications etc.) are identical. 

• Instance DB 1-3: The actual parameters and the static data for controlling the 

feed pumps for ingredient A, ingredient B and for the agitator motor are 

different and are therefore stored in three instance DBs associated with FB1. 

• FC1: The inlet and feed valves for ingredients A and B and the drain valve also 

use a common logic block. As only the function "open and close" must be 

programmed, one single FC is sufficient. 


A-80 A5E00706944-01

Appendix 

A.5.2.2 

Assigning Symbolic Names 

Defining Symbolic Names 

Symbols are used in the sample program and they must be defined in the symbol 

table using STEP 7. The following tables show the symbolic names and the 

absolute addresses of the program elements used. 

Symbolic Addresses for Feed Pump, Agitator Motor, and Inlet Valves 

Symbolic Name Address Data Type Description 

Feed_pump_A_start I0.0 BOOL Starts the feed pump for ingredient A 

Feed_pump_A_stop I0.1 BOOL Stops the feed pump for ingredient A 

Flow_A I0.2 BOOL Ingredient A flowing 

Inlet_valve_A Q4.0 BOOL Activates the inlet valve for ingredient A 

Feed_valve_A Q4.1 BOOL Activates the feed valve for ingredient A 

Feed_pump_A_on Q4.2 BOOL Lamp for "feed pump ingredient A running" 

Feed_pump_A_off Q4.3 BOOL Lamp for "feed pump ingredient A not 

running" 

Feed_pump_A Q4.4 BOOL Activates the feed pump for ingredient A 

Feed_pump_A_fault Q4.5 BOOL Lamp for "feed pump A fault" 

Feed_pump_A_maint Q4.6 BOOL Lamp for "feed pump A maintenance" 

Feed_pump_B_start I0.3 BOOL Starts the feed pump for ingredient B 

Feed_pump_B_stop I0.4 BOOL Stops the feed pump for ingredient B 

Flow_B I0.5 BOOL Ingredient B flowing 

Inlet_valve_B Q5.0 BOOL Activates the inlet valve for ingredient A 

Feed_valve_B Q5.1 BOOL Activates the feed valve for ingredient B 

Feed_pump_B_on Q5.2 BOOL Lamp for "feed pump ingredient B running" 

Feed_pump_B_off Q5.3 BOOL Lamp for "feed pump ingredient B not 

running" 

Feed_pump_B Q5.4 BOOL Activates the feed pump for ingredient B 

Feed_pump_B_fault Q5.5 BOOL Lamp for "feed pump B fault" 

Feed_pump_B_maint Q5.6 BOOL Lamp for "feed pump B maintenance" 

Agitator_running I1.0 BOOL Response signal of the agitator motor 

Agitator_start I1.1 BOOL Agitator start button 

Agitator_stop I1.2 BOOL Agitator stop button 

Agitator Q8.0 BOOL Activates the agitator 

Agitator_on Q8.1 BOOL Lamp for "agitator running" 

Agitator_off Q8.2 BOOL Lamp for "agitator not running" 

Agitator_fault Q8.3 BOOL Lamp for "agitator motor fault" 

Agitator_maint Q8.4 BOOL Lamp for "agitator motor maintenance" 


A5E00706944-01 A-81

Appendix 

Symbolic Addresses for Sensors and Displaying the Level of the Tank 


Tank_below_max I1.3 BOOL Sensor "mixing tank not full" 

Tank_above_min I1.4 BOOL Sensor "mixing tank above minimum level" 

Tank_not_empty I1.5 BOOL Sensor "mixing tank not empty" 

Tank_max_disp Q9.0 BOOL Lamp for "mixing tank full" 

Tank_min_disp Q9.1 BOOL Lamp for "mixing tank below minimum level" 

Tank_empty_disp Q9.2 BOOL Lamp for "mixing tank empty" 

Symbolic Addresses for the Drain Valve 


Drain_open I0.6 BOOL Button for opening the drain valve 

Drain_closed I0.7 BOOL Button for closing the drain valve 

Drain Q9.5 BOOL Activates the drain valve 

Drain_open_disp Q9.6 BOOL Lamp for "drain valve open" 

Drain_closed_disp Q9.7 BOOL Lamp for "drain valve closed" 

Symbolic Addresses for the Other Program Elements 


EMER_STOP_off I1.6 BOOL EMERGENCY STOP switch 

Reset_maint I1.7 BOOL Reset switch for the maintenance lamps on all motors 

Motor_block FB1 FB1 FB for controlling pumps and motor 

Valve_block FC1 FC1 FC for controlling the valves 

DB_feed_pump_A DB1 FB1 Instance DB for controlling feed pump A 

DB_feed_pump_B DB2 FB1 Instance DB for controlling feed pump B 

DB_agitator DB3 FB1 Instance DB for controlling the agitator motor 


A-82 A5E00706944-01

Appendix 

A.5.2.3 

Creating the FB for the Motor 

What is Required of the FB? 

The FB for the motor contains the following logical functions: 

• There is a start and a stop input. 

• A series of interlocks allow the operation of the devices (pumps and agitator 

motor). The status of the interlocks is saved in the temporary local data (L 

stack) of OB1 ("Motor_enable," "Valve_enable") and is logically combined with 

the start and stop inputs when the FB for the motor is processed. 

• Feedback from the devices must appear within a certain time. Otherwise, it is 

assumed that an error or fault has occurred. The function then stops the motor. 

• The point in time and the duration of the response or error/fault cycle must be 

specified. 

• If the start button is pressed and the motor enabled, the device switches itself 

on and runs until the stop button is pressed. 

• When the device is switched on, a timer starts to run. If the response signal 

from the device is not received before the timer has expired, the device stops. 

Specifying the Inputs and Outputs 

The following figure shows the inputs and outputs of the general FB for the motor. 

 

 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 A-83

Appendix 

Defining the Parameters for the FB 

If you use a multiple instance FB for the motor (for controlling both pumps and the 

motor) you must define general parameter names for the inputs and outputs. 

The FB for the motor in the sample process requires the following: 

• It must have signals from the operator station to stop and start the motor and 

pumps. 

• It requires a response signal from the motor and pumps to indicate that the 

motor is running. 

• It must calculate the time between sending the signal to activate the motor and 

receiving the response signal. If no response signal is received in this time, the 

motor must be switched off. 

• It must turn the lamps on the operator station on and off. 

• It supplies a signal to activate the motor. 

These requirements can be specified as inputs and outputs to the FB. The 

following table shows the parameters of the FB for the motor in our sample 

process. 

Parameter Name Input Output In/Out 

Start 

n 

Stop 

n 

Response 

n 

Reset_maint 

n 

Timer_No 

n 

Response_Time 

n 

Fault 

n 

Start_Dsp 

n 

Stop_Dsp 

n 

Maint 

n 

Motor 

n 


A-84 A5E00706944-01

Appendix 

Declaring the Variables of the FB for the Motor 

You must declare the input, output, and in/out parameters of the FB for the motor. 

Address Declaration Name Type Initial Value 

0.0 IN Start BOOL FALSE 

0.1 IN Stop BOOL FALSE 

0.2 IN Response BOOL FALSE 

0.3 IN Reset_Maint BOOL FALSE 

2.0 IN Timer_No TIMER 

4.0 IN Response_Time S5TIME S5T#0MS 

6.0 OUT Fault BOOL FALSE 

6.1 OUT Start_Dsp BOOL FALSE 

6.2 OUT Stop_Dsp BOOL FALSE 

6.3 OUT Maint BOOL FALSE 

8.0 IN_OUT Motor BOOL FALSE 

10.0 STAT Time_bin WORD W#16#0 

12.0 STAT Time_BCD WORD W#16#0 

14.0 STAT Starts INT 0 

16.0 STAT Start_Edge BOOL FALSE 

With FBs, the input, output, in/out, and static variables are saved in the instance 

DB specified in the call statement. The temporary variables are stored in the L 

stack. 


A5E00706944-01 A-85

Appendix 

Programming the FB for the Motor 

In STEP 7, every block that is called by a different block must be created before 

the block containing its call. In the sample program, you must therefore create the 

FB for the motor before OB1. 

The code section of FB1 appears as follows in the STL programming language: 

Network 1 Start/stop and latching 

A( 

O #Start 

O #Motor 

) 

AN #Stop 

= #Motor 

Network 2 Startup monitoring 

A #Motor 

L #Response_Time 

SD #Timer_No 

AN #Motor 

R #Timer_No 

L #Timer_No 

T #Timer_bin 

LC #Timer_No 

T #Timer_BCD 

A #Timer_No 

AN #Response 

S #Fault 

R #Motor 

Network 3 Start lamp and fault reset 

A #Response 

= #Start_Dsp 

R #Fault 

Network 4 Stop lamp 

AN #Response 

= #Stop_Dsp 

Network 5 Counting the starts 

A #Motor 

FP #Start_Edge 

JCN lab1 

L #Starts 

+ 1 

T #Starts 

lab1: NOP 0 

Network 6 Maintenance lamp 

L #Starts 

L 50 

>=I 

= #Maint 


A-86 A5E00706944-01

Appendix 

Network 7 Reset counter for number of starts 

A #Reset_Maint 

A #Maint 

JCN END 

L 0 

T #Starts 

END: NOP 0 

Creating the Instance Data Blocks 

Create three data blocks and open them one after another. In the "New Data 

Block" dialog box select the option "Data block referencing a function block." In the 

"Reference" list box select "FB1." The data blocks are then specified as instance 

data blocks with a fixed assignment to FB1. 


A5E00706944-01 A-87

Appendix 

A.5.2.4 

Creating the FC for the Valves 

What is Required of the FC? 

The function for the inlet and feed valves and for the drain valve contains the 

following logical functions: 

• There is an input for opening and an input for closing the valves. 

• Interlocks allow the valves to be opened. The state of the interlocks is saved in 

the temporary local data (L stack) of OB1 ("Valve_enable") and is logically 

combined with the inputs for opening and closing when the FC for the valves is 

processed. 

The following table shows the parameters that must be transferred to the FC. 

Parameters for the Valves Input Output In/Out 

Open 

Close 

Dsp_Open 

Dsp_Closed 

Valve 

 

 

 

 

 

Specifying the Inputs and Outputs 

The following figure shows the inputs and outputs of the general FC for the valves. 

The devices that call the FB for the motor transfer input parameters. The FC for the 

valves returns output parameters. 

 

 

 

 

 

 


A-88 A5E00706944-01

Appendix 

Declaring the Variables of the FC for the Valves 

Just as with the FB for the motor, you must also declare the input, output, and 

in/out parameters for the FC for the valves (see following variable declaration 

table). 

Address Declaration Name Type Initial Value 

0.0 IN Open BOOL FALSE 

0.1 IN Close BOOL FALSE 

2.0 OUT Dsp_Open BOOL FALSE 

2.1 OUT Dsp_Closed BOOL FALSE 

4.0 IN_OUT Valve BOOL FALSE 

With FCs, the temporary variables are saved in the L stack. The input, output, and 

in/out variables are saved as pointers to the logic block that called the FC. 

Additional memory space in the L stack (after the temporary variables) is used for 

these variables. 

Programming the FC for the Valves 

The FC1 function for the valves must be created before OB1 since the called 

blocks must be created before the calling blocks. 

The code section of FC1 appears as shown below in the STL programming 

language: 

Network 1 Open/close and latching 

A( 

O #Open 

O #Valve 

) 

AN #Close 

= #Valve 

Network 2 Display "valve open" 

A #Valve 

= #Dsp_Open 

Network 3 Display "valve closed" 

AN #Valve 

= #Dsp_Closed 


A5E00706944-01 A-89

Appendix 

A.5.2.5 

Creating OB1 

OB1 decides the structure of the sample program. OB1 also contains the 

parameters that are transferred to the various functions, for example: 

• The STL networks for the feed pumps and the agitator motor supply the FB for 

the motor with the input parameters for starting ("Start"), stopping ("Stop"), for 

the response ("Response"), and for resetting the maintenance display 

("Reset_Maint"). The FB for the motor is processed in every cycle of the PLC. 

• If the FB for the motor is processed, the inputs Timer_No and Response_Time 

inform the function of the timer being used and which time must be measured. 

• The FC for the valves and the FB for the motors are processed in every 

program cycle of the programmable controller because they are called in OB1. 

The program uses the FB for the motor with different instance DBs to handle the 

tasks for controlling the feed pumps and the agitator motor. 

Declaring Variables for OB1 

The variable declaration table for OB1 is shown below. The first 20 bytes contain 

the start information of OB1 and must not be modified. 

Address Declaration Name Type 

0.0 TEMP OB1_EV_CLASS BYTE 

1.0 TEMP OB1_SCAN1 BYTE 

2.0 TEMP OB1_PRIORITY BYTE 

3.0 TEMP OB1_OB_NUMBR BYTE 

4.0 TEMP OB1_RESERVED_1 BYTE 

5.0 TEMP OB1_RESERVED_2 BYTE 

6.0 TEMP OB1_PREV_CYCLE INT 

8.0 TEMP OB1_MIN_CYCLE INT 

10.0 TEMP OB1_MAX_CYCLE INT 

12.0 TEMP OB1_DATE_TIME DATE_AND_TIME 

20.0 TEMP Enable_motor BOOL 

20.1 TEMP Enable_valve BOOL 

20.2 TEMP Start_fulfilled BOOL 

20.3 TEMP Stop_fulfilled BOOL 

20.4 TEMP Inlet_valve_A_open BOOL 

20.5 TEMP Inlet_valve_A_closed BOOL 

20.6 TEMP Feed_valve_A_open BOOL 

20.7 TEMP Feed_valve_A_closed BOOL 

21.0 TEMP Inlet_valve_B_open BOOL 

21.1 TEMP Inlet_valve_B_closed BOOL 

21.2 TEMP Feed_valve_B_open BOOL 

21.3 TEMP Feed_valve_B_closed BOOL 

21.4 TEMP Open_drain BOOL 

21.5 TEMP Close_drain BOOL 

21.6 TEMP Valve_closed_fulfilled BOOL 


A-90 A5E00706944-01

Appendix 

Creating the Program for OB1 

In STEP 7, every block that is called by a different block must be created before 

the block containing its call. In the sample program, you must therefore create both 

the FB for the motor and the FC for the valves before the program in OB1. 

The blocks FB1 and FC1 are called more than once in OB1; FB1 is called with 

different instance DBs: 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


A5E00706944-01 A-91

Appendix 

The code section of OB1 appears as shown below in the STL programming 

language: 

Network 1 Interlocks for feed pump A 

A "EMER_STOP_off" 

A "Tank_below_max" 

AN "Drain" 

= #Enable_Motor 

Network 2 Calling FB Motor for ingredient A 

A "Feed_pump_A_start" 

A #Enable_Motor 

= #Start_Fulfilled 

A( 

O "Feed_pump_A_stop" 

ON #Enable_Motor 

) 

= #Stop_Fulfilled 

CALL "Motor_block", "DB_feed_pump_A" 

Start :=#Start_Fulfilled 

Stop :=#Stop_Fullfilled 

Response :="Flow_A" 

Reset_Maint :="Reset_maint" 

Timer_No :=T12 

Reponse_Time:=S5T#7S 

Fault :="Feed_pump_A_fault" 

Start_Dsp :="Feed_pump_A_on" 

Stop_Dsp :="Feed_pump_A_off" 

Maint :="Feed_pump_A_maint" 

Motor :="Feed_pump_A" 

Network 3 Delaying the valve enable ingredient A 

A "Feed_pump_A" 

L S5T#1S 

SD T 13 

AN "Feed_pump_A" 

R T 13 

A T 13 

= #Enable_Valve 

Network 4 Inlet valve control for ingredient A 

AN "Flow_A" 


= #Close_Valve_Fulfilled 

CALL "Valve_block" 

Open :=#Enable_Valve 

Close :=#Close_Valve_Fulfilled 

Dsp_Open :=#Inlet_Valve_A_Open 

Dsp_Closed:=#Inlet_Valve_A_Closed 

Valve :="Inlet_Valve_A" 


A-92 A5E00706944-01

Appendix 

Network 5 Feed valve control for ingredient A 

AN "Flow_A" 






Dsp_Open :=#Feed_Valve_A_Open 

Dsp_Closed:=#Feed_Valve_A_Closed 

Valve :="Feed_Valve_A" 

Network 6 Interlocks for feed pump B 


A "Tank_below_max" 

AN "Drain" 

= "Enable_Motor 

Network 7 Calling FB Motor for ingredient B 

A "Feed_pump_B_start" 



A( 

O "Feed_pump_B_stop" 


) 


CALL "Motor_block", "DB_feed_pump_B" 



Response :="Flow_B" 




Fault :="Feed_pump_B_fault" 

Start_Dsp :="Feed_pump_B_on" 

Stop_Dsp :="Feed_pump_B_off" 

Maint :="Feed_pump_B_maint" 

Motor :="Feed_pump_B" 

Network 8 Delaying the valve enable ingredient B 

A "Feed_pump_B" 

L S5T#1S 

SD T 15 

AN "Feed_pump_B" 

R T 15 

A T 15 

= #Enable_Valve 


A5E00706944-01 A-93

Appendix 

Network 9 Inlet valve control for ingredient B 

AN "Flow_B" 






Dsp_Open :=#Inlet_Valve_B_Open 

Dsp_Closed:=#Inlet_Valve_B_Closed 

Valve :="Inlet_Valve_B" 

Network 10 Feed valve control for ingredient B 

AN "Flow_B" 






Dsp_Open :=#Feed_Valve_B_Open 

Dsp_Closed:=#Feed_Valve_B_Closed 

Valve :="Feed_Valve_B" 

Network 11 Interlocks for agitator 


A "Tank_above_min" 

AN "Drain" 

= #Enable_Motor 

Network 12 Calling FB Motor for agitator 

A "Agitator_start" 



A( 

O "Agitator_stop" 


) 


CALL "Motor_block", "DB_Agitator" 



Response :="Agitator_running" 




Fault :="Agitator_fault" 

Start_Dsp :="Agitator_on" 

Stop_Dsp :="Agitator_off" 

Maint :="Agitator_maint" 

Motor :="Agitator" 


A-94 A5E00706944-01

Appendix 

Network 13 Interlocks for drain valve 


A "Tank_not_empty" 

AN "Agitator" 

= "Enable_Valve 

Network 14 Drain valve control 

A "Drain_open" 

A #Enable_Valve 

= #Open_Drain 

A( 

O "Drain_closed" 

ON #Enable_Valve 

) 

= #Close_Drain 


Open :=#Open_Drain 

Close :=#Close_Drain 

Dsp_Open :="Drain_open_disp" 

Dsp_Closed :="Drain_closed_disp" 

Valve :="Drain" 

Network 15 Tank level display 

AN "Tank_below_max" 

= "Tank_max_disp" 

AN "Tank_above_min" 

= "Tank_min_disp" 

AN "Tank_not_empty" 

= "Tank_empty_disp" 


A5E00706944-01 A-95

Appendix 

A.5.3 

Example of Handling Time-of-Day Interrupts 

Structure of the User Program "Time-of-Day Interrupts" 

FC12 

OB10 

OB1 and OB80 

A.5.3.1 


Task 

Output Q 4.0 should be set in the time from Monday, 5.00 am to Friday, 8.00 pm. 

In the time from Friday, 8.00 pm to Monday, 5.00 am the output Q 4.0 should be 

reset. 

Translating into a User Program 

The following table shows the sub-tasks of the blocks used. 

Block 

OB1 

FC12 

Sub-Task 

Calls the function FC12 

Depending on the state of the output Q 4.0, the time-of-day interrupt 

status, and the inputs I 0.0 and I 0.1 

• Specify the starting time 

• Set the time-of-day interrupt 

• Activate the time-of-day interrupt 

• CAN_TINT 

OB10 

Depending on the current day of the week 

• Specify the starting time 

• Set or reset output Q 4.0 

• Set next time-of-day interrupt 

• Activate next time-of-day interrupt 

OB80 Set output Q 4.1 

Store start event information of OB80 in bit memory area 


A-96 A5E00706944-01

Appendix 

Addresses Used 

The following table shows the shared addresses used. The temporary local 

variables are declared in the declaration section of the respective block. 

Address Meaning 

I0.0 Input to enable "set time-of-day interrupt" and "activate time-of-day 

interrupt" 

I0.1 Input to cancel a time-of-day interrupt 

Q4.0 Output set/reset by the time-of-day interrupt OB (OB10) 

Q4.1 Output set by a time error (OB80) 

MW16 

MB100 to 

MB107 

MB110 to 

MB129 

MW200 

MB202 

MW204 

MW208 

STATUS of the time-of-day interrupt (SFC31 "QRY_TINT") 

Memory for start event information of OB10 (time-of-day only) 

Memory for start event information of OB80 (time error) 

RET_VAL of SFC28 "SET_TINT" 

Binary result (status bit BR) buffer for SFCs 

RET_VAL of SFC30 "ACT_TINT" 

RET_VAL of SFC31 "QRY_TINT" 

System Functions and Functions Used 

The following system functions are used in the programming example: 

• SFC28 "SET_TINT" : Set Time-of-Day Interrupt 

• SFC29 "CAN_TINT" : Cancel Time-of-Day Interrupt 

• SFC30 "ACT_TINT" : Activate Time-of-Day Interrupt 

• SFC31 "QRY_TINT" : Query Time-of-Day Interrupt 

• FC3 "D_TOD_DT" : Combine DATE and TIME_OF_DAY to DT 


A5E00706944-01 A-97

Appendix 

A.5.3.2 

FC12 

Declaration Section 

The following temporary local variables are declared in the declaration section of 

FC12: 

Variable Name Data Type Declaration Comment 

IN_TIME TIME_OF_DAY TEMP Start time 

IN_DATE DATE TEMP Start date 

OUT_TIME_DATE DATE_AND_TIME TEMP Start date/time converted 

OK_MEMORY BOOL TEMP Enable for setting time-of-day 

interrupt 

STL Code Section 

Enter the following STL user program in the code section of FC12: 

STL (FC12) 

Network 1 

CALL SFC 31 

OB_NO := 10 

RET_VAL:= MW 208 

STATUS := MW 16 

Network 2: 

AN Q 4.0 

JC mond 

L D#1995-1-27 

T #IN_DATE 

L TOD#20:0:0.0 

T #IN_TIME 

JU cnvrt 

mond: L D#1995-1-23 

T #IN_DATE 

L TOD#5:0:0.0 

T #IN_TIME 

cnvrt: NOP 0 

Explanation 

SFC QRY_TINT 

Query STATUS of time-of-day interrupts 

Specify start time dependent on Q 4.0 

(in variable 

#IN_DATE and #IN_TIME) 

Start date is a Friday 

Start date is a Monday 


A-98 A5E00706944-01

Appendix 

STL (FC12) 

Network 3: 

CALL FC 3 

IN1 := #IN_DATE 

IN2 := #IN_TIME 

RET_VAL := #OUT_TIME_DATE 

Network 4: 

A I 0.0 

AN M 17.2 

A M 17.4 

= #OK_MEMORY 

Network 5: 

A #OK_MEMORY 

JNB m001 

CALL SFC 28 

OB_NO := 10 

SDT := #OUT_TIME_DATE 

PERIOD := W#16#1201 

RET_VAL := MW 200 

m001 A BR 

= M 202.3 

Network 6: 

A #OK_MEMORY 

JNB m002 

CALL SFC 30 

OB_NO := 10 


m002 A BR 

= M 202.4 

Network 7: 

A I 0.1 

JNB m003 

CALL SFC 29 

OB_NO := 10 


m003 A BR 

= M 202.5 

Explanation 

Convert format from DATE and TIME_OF_DAY 

to DATE_AND_TIME (for setting time-ofday 

interrupt) 

All requirements for setting time-of-day 

interrupt fulfilled? (Input for enable 

set and time-of-day interrupt not active 

and time-of-day interrupt OB is loaded) 

If so, set time-of-day interrupt... 

...and activate time-of-day interrupt. 

If input for canceling time-of-day 

interrupts is set, cancel time-of-day 

interrupt. 


A5E00706944-01 A-99

Appendix 

A.5.3.3 

OB10 


In contrast to the default declaration section of OB10 the following temporary local 

variables are declared: 

• Structure for the entire start event information (STARTINFO) 

• Within the STARTINFO structure a structure for the time (T_STMP) 

• Other temporary local variables WDAY, IN_DATE, IN_TIME, and 

OUT_TIME_DATE 


STARTINFO STRUCT TEMP Entire start event information of 

OB10 declared as structure 

E_ID WORD TEMP Event ID: 

PR_CLASS BYTE TEMP Priority class 

OB_NO BYTE TEMP OB number 

RESERVED_1 BYTE TEMP Reserved 


PERIOD WORD TEMP Periodicity of time-of-day 

interrupt 

RESERVED_3 DWORD TEMP Reserved 

T_STMP STRUCT TEMP Structure for time-of-day details 

YEAR BYTE TEMP 

MONTH BYTE TEMP 

DAY BYTE TEMP 

HOUR BYTE TEMP 

MINUTES BYTE TEMP 

SECONDS BYTE TEMP 

MSEC_WDAY WORD TEMP 

END_STRUCT TEMP 


WDAY INT TEMP Day of the week 

IN_DATE DATE TEMP Input variable for FC3 

(conversion of time format) 

IN_TIME TIME_OF_DAY TEMP Input variable for FC3 

(conversion of time format) 

OUT_TIME_DATE DATE_AND_TIME TEMP Output variable for FC3 and 

input variable for SFC28 


A-100 A5E00706944-01

Appendix 

STL Code Section 

Enter the following STL user program in the code section of OB10: 

STL (OB10) 

Network 1 

L #STARTINFO.T_STMP.MSEC_WDAY 

L W#16#F 

AW 

T #WDAY 

Network 2: 

L #WDAY 

L 2 

I 

JC mond 

Network 3: 

L D#1995-1-27 

T #IN_DATE 

L TOD#20:0:0.0 

T #IN_TIME 

SET 

= Q 4.0 

JU cnvrt 

mond: L D#1995-1-23 

T #IN_DATE 

L TOD#5:0:0.0 

T #IN_TIME 

CLR 

= Q 4.0 

cnvrt: NOP 0 

Network 4: 

CALL FC 3 

IN1 := #IN_DATE 

IN2 := #IN_TIME 

RET_VAL := #OUT_TIME_DATE 

Network 5: 

CALL SFC 28 

OB_NO := 10 

SDT := #OUT_TIME_DATE 

PERIOD := W#16#1201 


A BR 

= M 202.1 

Network 6: 

CALL SFC 30 

OB_NO := 10 


A BR 

= M 202.2 

Network 7: 

CALL SFC 20 

SRCBLK := #STARTINFO.T_STMP 


DSTBLK := P#M 100.0 BYTE 8 

Explanation 

Select day of week 

and store. 

If day of week is not Monday, then 

specify Monday, 5.00 am as next starting 

time and reset output Q 4.0. 

Otherwise, if day of week is Monday, 

specify Friday, 8.00 pm (20.00) as next 

starting time and set output Q 4.0. 

Starting time specified. 

Convert specified starting time to 

format DATE_AND_TIME (for SFC28). 

Set time-of-day interrupt. 

Activate time-of-day interrupt. 

Block transfer: save time of day from 

start event information of OB10 to the 

memory area MB100 to MB107. 


A5E00706944-01 A-101

Appendix 

A.5.3.4 


As the start event information of OB1 (OB for cyclic program) is not evaluated in 

this example, only the start event information of OB80 is displayed. 

OB1 Code Section 


STL (OB1) 

Explanation 

CALL FC 12 Calls the function FC12 

OB80 Declaration Section 






STARTINFO STRUCT TEMP Entire start event information of OB80 

declared as structure 


PR_CLASS BYTE TEMP Priority class 




A1_INFO WORD TEMP Additional information about the event 

that caused the error 

A2_INFO DWORD TEMP Additional information about the event 

ID, priority class, and OB no. of the 

error 




DAY BYTE TEMP 








A-102 A5E00706944-01

Appendix 

OB80 Code Section 

Enter the following STL user program in the code section of OB80 that is called by 

the operating system if a time error occurs: 

STL (OB80) 

Network 1 

AN Q 4.1 

S Q 4.1 

CALL SFC 20 

SRCBLK := #STARTINFO 


DSTBLK := P#M 110.0 Byte 20 

Explanation 

Set output Q 4.1 if time error occurred. 

Block transfer: save entire start event 

information to memory area MB110 to 

MB129. 


A5E00706944-01 A-103

Appendix 

A.5.4 

Example of Handling Time-Delay Interrupts 


FC12 

OB10 


A.5.4.1 

Structure of the User Program "Time-Delay Interrupts" 

Task 

When input I 0.0 is set, output Q 4.0 should be set 10 seconds later. Every time 

input I 0.0 is set, the delay time should be restarted. 

The time (seconds and milliseconds) of the start of the time-delay interrupt should 

appear as a user-specific ID in the start event information of the time-delay 

interrupt OB (OB20). 

If I 0.1 is set in these 10 seconds, the organization block OB20 should not be 

called; meaning the output Q 4.0 should not be set. 

When input I 0.2 is set, output Q 4.0 should be reset. 

Translating into a User Program 

The following table shows the sub-tasks of the blocks used. 

Block 

OB1 

Sub-Task 

Read current time and prepare for start of time-delay interrupt 

Dependent on edge change at input I 0.0, start time-delay interrupt 

Depending on the status of the time-delay interrupt and the edge change at 

input I 0.1, cancel time-delay interrupt 

Dependent on the state of input I 0.2, reset output Q 4.0 

OB20 Set output Q 4.0 

Read and prepare current time 

Save start event information to bit memory area 


A-104 A5E00706944-01

Appendix 

Addresses Used 

The following table shows the shared addresses used. The temporary local 

variables are declared in the declaration section of the respective block. 

Address 

Meaning 

I0.0 Input to enable "start time-delay interrupt" 

I0.1 Input to cancel a time-delay interrupt 

I0.2 Input to reset output Q 4.0 

Q4.0 Output set by the time-delay interrupt OB (OB20) 

MB1 

MW4 

MD10 

MW 100 

MW102 

MW104 

MW106 

MB120 to MB139 

MD140 

MW144 

Used for edge flag and binary result (status bit BR) buffer for SFCs 

STATUS of time-delay interrupt (SFC34 "QRY_TINT") 

Seconds and milliseconds BCD-coded from the start event 

information of OB1 

RET_VAL of SFC32 "SRT_DINT" 

RET_VAL of SFC34 "QRY_DINT" 

RET_VAL of SFC33 "CAN_DINT" 

RET_VAL of SFC20 "BLKMOV" 

Memory for start event information of OB20 


information of OB20 


information of OB1; acquired from start event information of OB20 

(user-specific ID SIGN) 

System Functions Used 

The following SFCs are used in the user program "time-delay interrupts:" 

• SFC32 "SRT_DINT" : Start Time-Delay Interrupt 

• SFC33 "CAN_DINT" : Cancel Time-Delay Interrupt 

• SFC34 "QRY_DINT" : Query Status of a Time-Delay Interrupt 


A5E00706944-01 A-105

Appendix 

A.5.4.2 

OB20 







STARTINFO STRUCT TEMP Start information for OB20 


PC_NO BYTE TEMP Priority class 


D_ID 1 BYTE TEMP Data ID 1 


SIGN WORD TEMP User-specific ID 

DTIME TIME TEMP Time with which the time-delay 

interrupt is started 


(time stamp) 



DAY BYTE TEMP 








A-106 A5E00706944-01

Appendix 

Code Section 


STL (OB20) 

Network 1 

SET 

= Q 4.0 

Network 2: 

L QW 4 

T PQW 4 

Network 3: 

L #STARTINFO.T_STMP.SECONDS 

T MW 140 


T MW 142 

L MD 140 

SRD 4 

T MD 140 

Network 4: 

L #STARTINFO.SIGN 

T MW 144 

Network 5: 

CALL SFC 20 

SRCBLK := STARTINFO 


DSTBLK := P#M 120.0 Byte 20 

Explanation 

Set output Q 4.0 unconditionally 

Activate output word immediately 

Read seconds from start event 

information 

Read milliseconds and day of week from 

start event information 

Eliminate day of week and 

write milliseconds back (now BCD-coded 

in MW 142) 

Read starting time of time-delay 

interrupt (= call SFC32) from start 

event information 

Copy start event information to memory 

area (MB120 to MB139) 


A5E00706944-01 A-107

Appendix 

A.5.4.3 

OB1 







STARTINFO STRUCT TEMP Start information for OB1 


PC_NO BYTE TEMP Priority class 




CUR_CYC INT TEMP Current cycle time 

MIN_CYC INT TEMP Minimum cycle time 

MAX_CYC INT TEMP Maximum cycle time 

T_STMP STRUCT TEMP Structure for time-of-day 

details (time stamp) 



DAY BYTE TEMP 








A-108 A5E00706944-01

Appendix 

Code Section 


STL (OB1) 

Network 1 

L #STARTINFO.T_STMP.SECONDS 

T MW 10 


T MW 12 

L MD 10 

SRD 4 

T MD 10 

Network 2: 

A I 0.0 

FP M 1.0 

= M 1.1 

Network 3: 

A M 1.1 

JNB m001 

CALL SFC 32 

OB_NO := 20 

DTME := T#10S 

SIGN := MW 12 


m001: NOP 0 

Network 4: 

CALL SFC 34 

OB_NO := 20 


STATUS := MW 4 

Network 5: 

A I 0.1 

FP M 1.3 

= M 1.4 

Network 6: 

A M 1.4 

A M 5.2 

JNB m002 

CALL SFC 33 

OB_NO := 20 


m002: NOP 0 

A I 0.2 

R Q 4.0 

Explanation 

Read seconds from start event 

information 

Read milliseconds and day of week from 

start event information 

Eliminate day of week and 

write milliseconds back (now BCD-coded 

in MW 12) 

Positive edge at input I 0.0? 

If so, start time-delay interrupt 

(starting time of time-delay interrupt 

assigned to the parameter SIGN) 

Query status of time-delay interrupt 

(SFC QRY_DINT) 

Positive edge at input I 0.1? 

...and time-delay interrupt is activated 

(bit 2 of time-delay interrupt STATUS)? 

Then cancel time-delay interrupt 

Reset output Q 4.0 with input I 0.2 


A5E00706944-01 A-109

Appendix 

A.5.4.4 

Example of Masking and Unmasking Synchronous Errors 

The following example of a user program illustrates how to mask and unmask 

synchronous errors. Using SFC36 "MSK_FLT" the following errors are masked in 

the programming error filter: 

• Area length error when reading 

• Area length error when writing 

With a second call of SFC36 "MSK_FLT" an access area can also be masked: 

• I/O access error when writing 

With SFC38 "READ_ERR" the masked synchronous errors are queried. The "I/O 

access error when writing" is unmasked again with SFC37 "DMSK_FLT." 

Code Section 

Below you will find the OB1 in which the example of the user program was 

programmed in Statement List. 

STL (Network 1) 

AN M 255.0 

JNB m001 

CALL SFC 36 

PRGFLT_SET_MASK 

ACCFLT_SET_MASK 

:=DW#16#C 

:=DW#16#0 

RET_VAL :=MW 100 

PRGFLT_MASKED :=MD 10 

ACCFLT_MASKED :=MD 14 

Explanation 

Non-retentive memory bit M 255.0 (only 

in first run = 0) 

SFC36 MSK_FLT (mask synchronous errors) 

Bit 2 = Bit 3 = 1 (BLFL and BLFS are 

masked) 

All bits=0 (no access errors are masked) 

Return value 

Output current programming error filter 

to MD10 

Output current access error filter to 

MD14 

Set M255.0 if masking successful 

m001: A BR 

S M 255.0 


CALL SFC 36 

PRGFLT_SET_MASK 

ACCFLT_SET_MASK 

:=DW#16#0 

:=DW#16#8 




Explanation 

SFC36 MSK_FLT (mask synchronous errors) 

All bits=0 (no further programming 

errors masked) 

Bit 3 = 1 (write access errors are 

masked) 

Return value 


to MD20 


MD24 


A-110 A5E00706944-01

Appendix 


AN M 27.3 

BEC 

Explanation 

Block end if write access error (bit 3 

in ACCFLT_MASKED) not masked 


L 

B#16#0 

Explanation 

T PQB 16 Write access (with value 0) to 

PQB 16 


CALL SFC 38 

PRGFLT_QUERY 

ACCFLT_QUERY 

:=DW#16#0 

:=DW#16#8 

Explanation 

SFC38 READ_ERR (query 

synchronous errors) 

All bits=0 (no programming 

errors queried) 

Bit 3 = 1 (write access error 

queried) 

Return value 


PRGFLT_CLR :=MD 30 

ACCFLT_CLR :=MD 34 

Output current programming error 

filter to MD30 

Output current access error 

filter to MD34 

No error occurred and write 

access error detected 

A 

BR 

Invert RLO 

M 0.0=1 if PQB 16 present 

A M 37.3 

NOT 

= M 0.0 


L 

B#16#0 

Explanation 


PQB 17 


A5E00706944-01 A-111

Appendix 


CALL SFC 38 

A 

PRGFLT_QUERY 

ACCFLT_QUERY 

:=DW#16#0 

:=DW#16#8 




BR 

A M 37.3 

NOT 

= M 0.1 

Explanation 

SFC38 READ_ERR (query synchronous 

errors) 

All bits=0 (no programming errors 

queried) 

Bit 3 = 1 (write access error queried) 

Return value 


to MD30 


MD34 

No error occurred and write access error 

detected 

Invert RLO 



Explanation 

L B#16#0 

T PQB 18 Write access (with value 0) to PQB 18 


CALL SFC 38 

A 

PRGFLT_QUERY 

ACCFLT_QUERY 

:=DW#16#0 

:=DW#16#8 




BR 

A M 37.3 

NOT 

= M 0.2 

Explanation 


errors) 


queried) 


Return value 


to MD30 


MD34 


detected 

Invert RLO 



Explanation 

L B#16#0 


PQB 19 


A-112 A5E00706944-01

Appendix 


CALL SFC 38 

A 

PRGFLT_QUERY 

ACCFLT_QUERY 

:=DW#16#0 

:=DW#16#8 




BR 

A M 37.3 

NOT 

= M 0.3 

Explanation 


errors) 


queried) 


Return value 


to MD30 


MD34 


detected 

Invert RLO 



CALL SFC 37 

PRGFLT_RESET_MASK 

ACCFLT_RESET_MASK 

:=DW#16#0 

:=DW#16#8 




Explanation 

SFC37 DMSK_FLT (unmask synchronous 

errors) 

All bits=0 (no further programming 

errors unmasked) 

Bit 3 = 1 (write access error unmasked) 

Return value 


to MD20 


MD24 


A M 27.3 

BEC 

Explanation 

Block end if write access error (bit 3 

in ACCFLT_MASKED) not unmasked 


A M 0.0 

JNB m002 

L IB 0 

T PQB 16 

m002: NOP 0 

Explanation 

Transfer IB0 to PQB 16 if present 


A M 0.1 

JNB m003 

L IB 1 

T PQB 17 

m003: NOP 0 

Explanation 



A M 0.2 

JNB m004 

L IB 2 

T PQB 18 

m004: NOP 0 

Explanation 



A5E00706944-01 A-113

Appendix 


A M 0.3 

JNB m005 

L IB 3 

T PQB 19 

m005: NOP 0 

Explanation 



A-114 A5E00706944-01

Appendix 

A.5.4.5 

Example of Disabling and Enabling Interrupts and 

Asynchronous Errors (SFC39 and SFC40) 

In this example of a user program, a program section is assumed that cannot be 

interrupted by interrupts. For this program section, OB35 calls (time-of-day 

interrupt) are disabled using SFC 39 "DIS_IRT" and later enabled again using 

SFC 40 "EN_IRT". 

SFC39 and SFC40 are called in OB1: 

STL (OB1) 

A M 0.0 

S M 90.1 

A M 0.1 

S M 90.0 

: 

: 

CALL SFC 39 

MODE :=B#16#2 

OB_NO :=35 


: 

: 

L PIW 100 

T MW 200 

L MW 90 

T MW 92 

: 

: 

CALL SFC 40 

MODE :=B#16#2 

OB_NO :=35 


Explanation 

Program section that can be interrupted 

without problems: 

Program section that must not be 

interrupted by interrupts: 

Disable and discard interrupts 

Mode 2: disable individual interrupt OBs 

Disable OB35 

Enable interrupts 

Mode 2: enable individual interrupt OBs 

Enable OB35 



A M 10.0 

S M 190.1 

A M 10.1 

S M 190.0 

: 

: 


A5E00706944-01 A-115

Appendix 

A.5.4.6 

Example of the Delayed Processing of Interrupts and 

Asynchronous Errors (SFC41 and SFC42) 

In this example of a user program, a program section is assumed that cannot be 

interrupted by interrupts. For this program section, interrupts are delayed using 

SFC41 "DIS_AIRT" and later enabled again using SFC42 "EN_AIRT." 

SFC41 and SFC42 are called in OB1: 

STL (OB1) 

A M 0.0 

S M 90.1 

A M 0.1 

S M 90.0 

: 

: 

CALL SFC 41 


L PIW 100 

T MW 200 

L MW 90 

T MW 92 

: 

: 

: 

CALL SFC 42 


L MW 100 

DEC 1 

L MW 102 

I 

JC 

err 

Explanation 



Program section that must not be 

interrupted by interrupts: 

Disable and delay interrupts 

Enable interrupts 

The number of set interrupt disables is 

in the return value 


in the return value 

The number must have the same value 

after the interrupt is enabled 

as before the interrupt disable (here 

"0") 

A M 10.0 

S M 190.1 

A M 10.1 

S M 190.0 

: 

: 

BEU 

err: L MW 102 

T QW 12 




displayed 


A-116 A5E00706944-01

Appendix 

A.6 Accessing Process and I/O Data Areas 

A.6.1 

Accessing the Process Data Area 

The CPU can access inputs and outputs of central and distributed digital 

input/output modules either indirectly using the process image tables or directly via 

the backplane/P bus. 

The CPU accesses inputs and outputs of central and distributed analog 

input/output modules directly via the backplane/P bus. You can also enter the 

addresses of analog modules in the process image area. 

Addressing Modules 

You assign the addresses used in your program to the modules when you 

configure the modules with STEP 7, as follows: 

• With central I/O modules: arrangement of the rack and assignment of the 

modules to slots in the configuration table. 

• For stations with a distributed I/O (PROFIBUS DP or PROFINET IO): 

arrangement of the DP slaves or IO devices with the PROFIBUS address or 

device name and assignment of the modules to slots. 

By configuring the modules, it is no longer necessary to set addresses on the 

individual modules using switches. As a result of the configuration, the 

programming device sends data to the CPU that allow the CPU to recognize the 

modules assigned to it. 

Peripheral I/O Addressing 

There is a separate address area for inputs and outputs. This means that the 

address of a peripheral area must not only include the byte or word access type but 

also the I identifier for inputs and Q identifier for outputs. 

The following table shows the available peripheral address areas. 

Address Area Access via Units of Following Size S7 Notation (IEC) 

Peripheral (I/O) area: 

inputs 

Peripheral (I/O) area: 

outputs 

Peripheral input byte 

Peripheral input word 

Peripheral input double word 

Peripheral output byte 

Peripheral output word 

Peripheral output double word 

PIB 

PIW 

PID 

PQB 

PQW 

PQD 

To find out which address areas are possible on individual modules, refer to the 

following manuals: 

• CPU 31xC and CPU 31x, Technical Data 

• S7-400 Programmable Controllers, CPU Data 


A5E00706944-01 A-117

Appendix 

Module Start Address 

The module start address is the lowest byte address of a module. It represents the 

start address of the user data area of the module and is used in many cases to 

represent the entire module. 

The module start address is, for example, entered in hardware interrupts, 

diagnostic interrupts, insert/remove module interrupts, and power supply error 

interrupts in the start information of the corresponding organization block and is 

used to identify the module that initiated the interrupt. 

A.6.2 

Accessing the Peripheral Data Area 

The peripheral data area can be divided into the following: 

• User data and 

• Diagnostic and parameter data. 

Both areas have an input area (can only be read) and an output area (can only be 

written). 

User Data 

User data is addressed with the byte address (for digital signal modules) or the 

word address (for analog signal modules) of the input or output area. User data can 

be accessed with load and transfer commands, communication functions (operator 

interface access), or by transferring the process image. User data can be any of 

the following: 

• Digital and analog input/output signals from signal modules 

• Control and status information from function modules 

• Information for point-to-point and bus connections from communication 

modules (only S7-300) 

When transferring user data, a consistency of a maximum of 4 bytes can be 

achieved (with the exception of DP standard slaves, see Setting the Operating 

Behavior). If you use the "transfer double word" statement, four contiguous and 

unmodified (consistent) bytes are transferred. If you use four separate "transfer 

input byte" statements, a hardware interrupt OB could be inserted between the 

statements and transfer data to the same address so that the content of the original 

4 bytes is changed before they were all transferred. 


A-118 A5E00706944-01

Appendix 

Diagnostic and Parameter Data 

The diagnostic and parameter data of a module cannot be addressed individually 

but are always transferred in the form of complete data records. This means that 

consistent diagnostic and parameter data are always transferred. 

The diagnostic and parameter data is accessed using the start address of the 

module and the data record number. Data records are divided into input and output 

data records. Input data records can only be read, output data records can only be 

written. You can access data records using system functions or communication 

functions (user interface). The following table shows the relationship between data 

records and diagnostic and parameter data. 

Data 

Description 

Diagnostic data If the modules are capable of diagnostics, you obtain the diagnostic data 

of the module by reading data records 0 and 1. 

Parameter data If the modules are configurable, you transfer the parameters to the 

module by writing data records 0 and 1. 

Accessing Data Records 

You can use the information in the data records of a module to reassign 

parameters to configurable modules and to read diagnostic information from 

modules with diagnostic capability. 

The following table shows which system functions you can use to access data 

records. 

SFC 

Purpose 

Assigning parameters to modules 

SFC55 WR_PARM Transfers the modifiable parameters (data record 1) to the addressed 

signal module 

SFC56 

WR_DPARM 

SFC57 

PARM_MOD 

SFC58 WR_REC 

Transfers parameters from SDBs 100 to 129 to the addressed signal 

module 

Transfers parameters from SDBs 100 to 129 to the addressed signal 

module 

Transfers any data record to the addressed signal module 

Reading out diagnostic information 

SFC59 RD_REC Reads the diagnostic data 

Note 

If a DPV1 slave is configured using a GSD file (GSD as of Rev. 3) and the DP 

interface of the DP master is set to "S7 compatible", then data records must not be 

read from or written to the I/O modules in the user program with SFC 58/59 or 

SFB 53/52. The reason is that in this case the DP master addresses the incorrect 

slot (configured slot +3). 

Remedy: Set the interface for the DP master to "DPV1". 


A5E00706944-01 A-119

Appendix 

Addressing S5 Modules 

You can access S5 modules as follows: 

• By connecting an S7-400 to SIMATIC S5 expansion racks using the interface 

module IM 463-2 

• By plugging in certain S5 modules in an adapter casing in the central rack of 

the S7-400 

How you address S5 modules with SIMATIC S7 is explained in the "S7-400, 

M7-400 Programmable Controllers, Hardware and Installation" Manual or the 

description supplied with the adapter casing. 

A.7 Setting the Operating Behavior 

This chapter explains how you can modify certain properties of S7-300 and S7-400 

programmable controllers by setting system parameters or using system functions 

(SFCs). 

You will find detailed information on the module parameters in the STEP 7 online 

help and in the following manuals: 



Manual 


Manual 

You will find all you need to know about SFCs in the "System Software for S7-300 

and S7-400, System and Standard Functions" Reference Manual. 

Addressing DP Standard Slaves 

If you want to exchange data longer than 4 bytes with DP standard slaves, you 

must use special SFCs for this data exchange. 

CPUs that support the exchange of consistent data (> 4 bytes) by means of the I/O 

area do not need SFCs 14/15 (see Distributed Reading and Writing of Consistent 

Data). 

SFC 

Purpose 

Assigning parameters to modules 

SFC15 

DPWR_DAT 

Reading out diagnostic information 

SFC13 

DPNRM_DG 

SFC14 

DPRD_DAT 

Transfers any data to the addressed signal module 

Reads the diagnostic information (asynchronous read access) 

Reads consistent data (length 3 or greater than 4 bytes) 

When a DP diagnostic frame arrives, a diagnostic interrupt with 4 bytes of 

diagnostic data is signaled to the CPU. You can read out these 4 bytes using 

SFC13 DPNRM_DG. 


A-120 A5E00706944-01

Appendix 

A.7.1 

Changing the Behavior and Properties of Modules 

Default Settings 

• When supplied, all the configurable modules of the S7 programmable controller 

have default settings suitable for standard applications. With these defaults, 

you can use the modules immediately without making any settings. The default 

values are explained in the module descriptions in the following manuals: 



Manual 


Manual 

Which Modules Can You Assign Parameters To? 

You can, however, modify the behavior and the properties of the modules to adapt 

them to your requirements and the situation in your plant. Configurable modules 

are CPUs, FMs, CPs, and some of the analog input/output modules and digital 

input modules. 

There are configurable modules with and without backup batteries. 

Modules without backup batteries must be supplied with data again following any 

power down. The parameters of these modules are stored in the retentive memory 

area of the CPU (indirect parameter assignment by the CPU). 

Setting and Loading Parameters 

You set module parameters using STEP 7. When you save the parameters, 

STEP 7 creates the object "System Data Blocks" that is downloaded to the CPU 

with the user program and transferred to the modules when the CPU starts up. 


A5E00706944-01 A-121

Appendix 

Which Settings Can Be Made? 

The module parameters are divided into parameter blocks. Which parameter 

blocks are available on which CPU is explained in the "S7-300 Programmable 

Controller, Hardware and Installation" Manual and the "S7-400, M7-400 

Programmable Controllers, Module Specifications" Reference Manual. 

Examples of parameter blocks: 

• Startup behavior 

• Cycle 

• MPI 

• Diagnostics 

• Retentive data 

• Clock memory 

• Interrupt handling 

• Onboard I/Os (only for the S7-300) 

• Protection level 

• Local data 

• Real-time clock 

• Asynchronous errors 


A-122 A5E00706944-01

Appendix 

Parameter Assignment with SFCs 

In addition to assigning parameters with STEP 7, you can also include system 

functions in the S7 program to modify module parameters. The following table 

shows which SFCs transfer which module parameters. 

SFC 

SFC55 WR_PARM 

SFC56 WR_DPARM 

SFC57 PARM_MOD 

SFC58 WR_REC 

Purpose 

Transfers the modifiable parameters (data record 1) to the 

addressed signal module 

Transfers the parameters from the corresponding SDBs to the 


Transfers all parameters from the corresponding SDBs to the 


Transfers any data record to the addressed signal module 

The system functions are described in detail in the "System Software for S7-300 

and S7-400, System and Standard Functions" Reference Manual. 

Which module parameters can be modified dynamically is explained in the 

following manuals: 



Manual 


Manual 


A5E00706944-01 A-123

Appendix 

A.7.2 

Updating the Firmware (of the Operating System) in Modules 

and Submodules Offline 

The following section describes how to transfer a new firmware version ( new 

operating system version) to a module or a CPU by means of a memory card. 

The update requires the following two steps: 

1. Create an "update memory card" (transfer the update files to a memory card) 

with the programming device (PG) or PC with an external prommer. 

2. Using the "update memory card", update the operating system on the CPU. 

Requirements 

• Memory card with sufficient storage capacity. For information on this, refer to 

the download pages at customer support. This is where you will also find the 

update files. 

• Programming device (PG) or PC set up to program memory cards. 

To transfer the update files to a memory card, proceed as follows: 

1. Create a new directory with the Windows Explorer. 

2. Transfer the desired update file to this directory and unzip it there. This 

directory will then contain the UPD file. 

3. Insert the S7 memory card into the programming device (PG) or the prommer. 

4. Delete the memory card (menu command: File > S7 Memory Card > Delete in 

the SIMATIC Manager). 

5. Select the PLC > Update Operating System menu command in the SIMATIC 

Manager. 

6. In the dialog box that is displayed, select the directory with the UPD files. 

7. Double-click the UPD file. 

This action starts the programming process. When this process is ended, the 

message "The firmware update for the module was successfully transferred to 

the S7 memory card" is displayed. 

Updating the Operating System: 

1. Insert the memory card with the update into the PLC (i.e. in the CPU) 

2. Switch off the power supply (PS) unit for the CPU. 

3. Insert the prepared memory card with the update into the CPU. 

4. Switch the power for the CPU back on. 

The operating system is transferred from the S7 memory card to the internal 

FLASH EPROM. 

During this time, all LEDs on the CPU are lit up. 

5. After about two minutes, the update is finished. To indicate that the update is 

finished, the STOP LED on the CPU flashes slowly (system request for 

memory reset) 


A-124 A5E00706944-01

Appendix 

6. Switch the power off at the power supply unit and, where appropriate, insert 

the S7 memory card that is intended for the operation. 

7. Switch the power back on. The CPU executes an automatic memory reset. 

After that, the CPU is ready for operation. 

8. Updating Firmware in Modules and Submodules 


A5E00706944-01 A-125

Appendix 

A.7.3 

Using the Clock Functions 

All S7-300/S7-400 CPUs are equipped with a clock (real-time clock or software 

clock). The clock can be used in the programmable controller both as clock master 

or clock slave with external synchronization. The clock is required for Time-Of-Day 

interrupts and runtime meters. 

Time Format 

The clock always indicates the time (minimum resolution 1 s), date, and weekday. 

With some CPUs it is also possible to indicate milliseconds (refer to the "S7-300 

Programmable Controller, Hardware and Installation" Manual and "S7-400, M7-400 

Programmable Controllers Module Specifications" Reference Manual). 

Setting and Reading the Time 

You set the time and date for the CPU clock by calling SFC0 SET_CLK in the user 

program or with a menu option on the programming device to start the clock. Using 

SFC1 READ_CLK or a menu option on the programming device, you can read the 

current date and time on the CPU. 

Note 

To prevent the time from being displayed differently on HMI systems, you should 

set winter time on the CPU. 

Assigning Parameters for the Clock 

If more than one module equipped with a clock exists in a network, you must set 

parameters using STEP 7 to specify which CPU functions as master and which as 

slave when the time is synchronized. When setting these parameters, you also 

decide whether the time is synchronized via the communication bus or via the 

multipoint interface and the intervals at which the time is automatically 

synchronized. 

Synchronizing the Time 

To make sure that the time is the same on all modules in the network, the slave 

clocks are synchronized by the system program at regular (selectable) intervals. 

You can transfer the date and time from the master clock to the slave clocks using 

system function SFC48 SFC_RTCB. 


A-126 A5E00706944-01

Appendix 

Using a Runtime Meter 

A runtime meter counts the operating hours of connected equipment or the total 

runtime hours of the CPU. 

In STOP mode, the runtime meter is stopped. Its count value is retained even after 

a memory reset. During a restart (warm restart), the runtime meter must be 

restarted by the user program; during a hot restart, it continues automatically if it 

had already been started. 

You can set the runtime meter to an initial value using SFC2 SET_RTM. You can 

start or stop the runtime meter with SFC3 CTRL_RTM. You can read the current 

total operating hours and the state of the counter ("stopped" or "counting") with 

SFC4 READ_RTM. 

A CPU can have up to eight run-time meters. Numbering starts at 0. 


A5E00706944-01 A-127

Appendix 

A.7.4 

Using Clock Memory and Timers 

Clock Memory 

The clock memory is a memory byte that changes its binary state periodically at a 

pulse-pause ratio of 1:1. You select which memory byte is used on the CPU when 

you assign parameters for the clock memory using STEP 7. 

Uses 

You can use clock memory bytes in the user program, for example, to activate 

flashing lights or to trigger periodic activities (for example, measuring an actual 

value). 

Possible Frequencies 

Each bit of the clock memory byte is assigned a frequency. The following table 

shows the assignment: 

Bit of the Clock 

Memory Byte 

7 6 5 4 3 2 1 0 

Period Duration (s) 2.0 1.6 1.0 0.8 0.5 0.4 0.2 0.1 

Frequency (Hz) 0.5 0.625 1 1.25 2 2.5 5 10 

Note 

Clock memory bytes are not synchronous with the CPU cycle, in other words, in long cycles, 

the state of the clock memory byte may change several times. 

Timers 

Timers are a memory area of the system memory. You specify the function of a 

timer in the user program (for example, on-delay timer). The number of timers 

available depends on the CPU. 

Note 

• If you use more timers in your user program than the CPU permits, a 

synchronous error is signaled and OB121 started. 

• On the S7-300 (with the exception of the CPU 318), timers can be started and 

updated simultaneously only in OB1 and OB100; in all other OBs timers can 

only be started. 


A-128 A5E00706944-01

Index 

" 

"Accessible Nodes" Window 18-2 

* 

*.awl -File 6-25 

*.GSD File 7-1 

*.k7e -Datei 6-25 

*.k7p -File 6-25 

*.sdf -File 6-25 

A 

Absolute and Symbolic Addressing 8-1 

Access Rights 18-6 

Access Rights to Blocks and 

Source Files 10-4 

Accessing the Peripheral Data Area A-118 

Accessing the Process Data Area A-117 

ACT_TINT 4-25, 4-26 

Activating 8-14 

Display of Symbols in the Block 8-14 

Activating the Display of Symbols in the 

Block 8-14 

Actual Parameters 4-15 

Adding Associated Values to Messages 

16-28 

Address Areas A-18, A-19 

Address Assignments 

Checking 2-12 

Address Priority (Symbolic/Absolute) 8-5 

Addresses 

Inserting in a Variable Table 20-4 

Rewiring 9-19 

Without Symbols 14-10 

Addresses and Data Types Permitted in the 

Symbol Table 8-11 

Addresses Without Symbols 14-9 

Addressing 8-1, A-120 

Absolute 8-1, 8-2 

area-crossing A-54, A-55 

area-internal A-54 

DP Standard Slaves A-120 

Memory Indirect A-54 

Symbolic 8-1, 8-2, 8-4 

Addressing Modules A-117 

Addressing S5 Modules A-120 

ANY A-52, A-58, A-59, A-60, A-61, A-62, 

A-63 

Archive 

CPU Messages 16-39, 16-41 

Archiving 

Procedure 24-6 

Projects and Libraries 24-4 

Requirements 24-5 

STEP 7 V.2.1 Projects with Global Data 

Communication A-74 

Uses 24-5 

ARRAY A-41, A-44, A-45, A-46, A-47 

Assigning and Editing Block-Related 

Messages 16-12 

Assigning Data Types to Local Data of 

Logic Blocks A-64 

Assigning A-64 

Assigning Message Numbers 16-10 

Assigning Parameters 

Signal Modules with Hardware Interrupt 

Capability 4-30 

Assigning Parameters to Data Blocks 12-1 

Assigning Parameters to Technological 

Functions 12-2 

Assigning Parameters to the PG/PC 

Interface 2-11 

Assigning Symbolic Names A-81 

Assignment of Message Numbers 16-11 

Associated Value 

Adding to Messages 16-28 

Asynchronous Errors 23-27 

Delayed Processing A-116 

Disabling and Enabling A-115 

OB81 23-28, 23-29, 23-30 

Using OBs to React to Errors 4-35 

Attributes for Blocks and Parameters 9-19 

Automation License Manager 2-1 

Avoiding Errors when Calling Blocks 15-7 


A5E00706944-01 

Index-1

Index 

B 

B Stack 

Data saved in the B Stack A-26 

Nested Calls A-26 

Background OB 

Priority 4-33 

Programming 4-34 

Background OB (OB90) 4-33 

Background Organization Block 

(OB90) 4-33 

Basic Information 

on Data Blocks 11-1 

Basic Information on Programming in STL 



for Determining the Cause of a STOP 

23-15 

Planning an Automation Project 3-1 

when Printing 24-2 

Basic Procedure for 

Creating Logic Blocks 10-3 

Basic Time (see Module Time) 18-9 

Battery Backup A-30 

BCD A-39 

Binary Coded Decimal A-39 

Bit Messaging 16-1, 16-2 

BLKMOV A-17 

BLOCK A-52, A-53 

Block Calls 4-8, 4-9 

Block Comment 10-15 

Block Comments 

Entering 10-16 

Block Consistency 

Checking 15-1 

Block Folder 5-16 

Block Folder Object 5-16 

Block Folder Properties 9-15 

Displaying Block Lengths 9-15 

Block for Changing the Pointer A-55 

Block Lengths 9-15 

Displaying 9-15 

Block Properties 9-13, 9-14, 10-3 

Block Property 

Time Stamp 15-3 

Block Stack A-15, A-26 

Block Title 10-15 

BLOCK_DB A-52 

BLOCK_FB A-52 

BLOCK_FC A-52 

BLOCK_SDB A-52 

Block-Related Messages (Project-Oriented) 

generating 16-13 

Blocks 15-1 


Attributes 9-19 

Comparing 9-18 

Creating with S7-GRAPH 9-8 

Deleting on the Programmable Controller 

19-19 

Entering in STL 10-13 

Reloading in the Programmable 

Controller 19-6 

Rewiring 9-19 

Saving 10-29 

Uploading from an S7 CPU 19-15 

Blocks Folder 9-11 

Blocks for Reporting System Errors 

Generating 16-49 

BOOL A-33 

Area A-33 

Boxes 

Positioning 10-19, 10-24 

Removing 

Changing 10-24 

Breakpoint Bar 21-4 

Browser 5-29 

Buttons 5-22 

Toolbar 5-22 

Buttons in the Toolbar 5-22 

BYTE A-33 

Area A-33 

C 

Call Hierarchy in the User Program 4-8 

Calling 

Module Information from the Project View 

(Online) 23-6 

Calling the Help Functions 5-5 

Calling the Quick View 23-5 

CAN_TINT 4-26 

Certificate of License 2-1, 2-3 

CFC 9-10 

CFC Program 25-1 

CFC Programming Language 9-2 

Changing Interfaces 10-28 

Changing Operator Control and Monitoring 

Attributes with CFC 17-5 

Changing the Behavior and Properties of 

Modules A-121 

Changing the Declaration Type 

changing 10-9 

Changing the Operating Mode 18-8 

Changing the Window Arrangement 5-31 

CHAR A-33 

Checking 13-19 

Consistency in STL Source Files 13-19 

Checking Block Consistency 15-1 

Checking Projects for Software Packages 

Used 6-14 

Checking Scan Cycle Times to Avoid Time 

Errors 23-17 

Choosing a Messaging Method 16-3 

Index-2 


A5E00706944-01

Index 

Clock A-126 

Parameter Assignment A-126 

Synchronizing A-126 

Clock Functions A-126 

Clock Memory A-128 

Code Section 10-3, 10-6 

Editing 10-12 

Search Function for Errors 10-18 

Structure 10-12 

Coils 

Positioning 10-20 

Combination Box 

Definition 5-23 

Comment Character 20-4 

Comment Line 20-4 

Comment Lines 

Inserting 20-9 

Comments 

for Blocks 10-15 

for Networks 10-15 

Communication Error (OB87) 23-42 

Communication Error Organization Block 

23-42 

Compare Preset and 

Actual Parameters A-5 

Comparing Blocks 9-16 

Comparing On-/Offline Partners 9-16 

Compatibility 7-1, 7-3, A-74 

Compatibility (DP slaves) A-74 

Compatibility (V2 Projects 

and Libraries 7-1 

Compiling 13-20 

STL Source Files 13-20 

Compiling and Downloading Objects 19-11 

Compiling Objects 19-11 

Complex Data Types A-41, A-44, A-45, 

A-48 

Compressing 19-21 

the Memory Contents of an 

S7 CPU 19-21 

User Memory 19-20 

Compressing the User Memory 19-20 

Configurable Memory Objects in the Work 

Memory A-31 

Configurable Modules A-121 

Configuration Data 17-1, 17-2 

Transferring 16-38, 17-6 

Configuration Diagram 

Creating 3-10 

Configuration Table 26-1 

Configuring CPU Messages 16-42 

Configuring Hardware 26-1 

Configuring Messages for System Errors 

16-43 

Configuring Operator Control and 

Monitoring Attributes via the Symbol 

Table 17-4 

Configuring Operator Control and 

Monitoring Attributes with Statement List 

Ladder Logic 

and Function Block Diagram 17-3 

Configuring the Reporting of System Errors 

16-43 

Configuring Variables for Operator Control 

and Monitoring 17-1 

Connection Table 6-11 

Connection Test (See Flashing Test) 18-2 

Connection to the CPU 

Establishing 20-13 

Context-Sensitive Help 5-5 

Continuing to Edit Version 2 Projects and 

Libraries 7-1 

Continuous Function Chart 9-2, 9-10 

Control at Contact 26-4 

Converting A-74 

Project with Global Data Communication 

A-74 

Converting Version 1 Projects A-72 

Converting Version 2 Projects A-73 

Copying/Moving Variable Tables 20-3 

Correcting a Memory Bottleneck 19-20 

Correcting the Interfaces 

in a Function 15-6 


or UDT 15-6 

Counter 14-6 

Assignment List 14-6, 14-7 

COUNTER A-52, A-53 

Memory Area 

Retentive A-29 

Counters 

Upper Limits for Entering 20-8 

CPU 22-1 

Operating Modes A-1, A-2 

Resetting 19-18 

Simulating 22-1 

CPU 31xC 6-22, 6-24, 6-25 

CPU Clocks with Time Zone Setting 18-9 

CPU Hardware Fault (OB84) 23-39 

CPU Hardware Fault Organization Block 

23-39 

CPU Messages 

Archive Size 16-39 


CPU Operating System A-124 

CPU Oriented 16-11 

CPU Redundancy Error (OB72) 23-34 

CREAT_DB A-16 

Creating 5-24, A-87 

FB for the Motor A-83, A-84, A-85, A-86 

FC for the Valves A-88, A-89 

OB1 for the Sample Industrial Blending 

Process A-90 

Objects 5-24 


A5E00706944-01 

Index-3

Index 


User Programs 10-3 

Variable Table 20-3 

Creating a Configuration Diagram 3-10 

Example of Industrial Blending Process 

3-10 

Creating a Data Block in 

Load Memory 6-22 

Creating a Project 6-9 

Creating a Sample FB for the Industrial 

Blending Process A-83 

Creating a Sample FC for the Industrial 


Creating an I/O Diagram for the Motors 3-6 

Creating an I/O Diagram for the Valves 3-7 

Creating an Input Diagram 

for the Motors 3-6 

Creating an Input Diagram 

for the Valves 3-7 

Creating an Object 5-24 

Creating an Output Diagram 


Creating an Output Diagram 


Creating and Editing User-Defined 

Diagnostic Messages 16-19 

Creating and Managing Objects 5-24 

Creating Foreign-Language Message Texts 

in Report System Error' 16-51 

Creating Sequential Controls 9-8 

with S7-GRAPH 9-8 

Creating User Text Libraries 16-34 

Cross-Reference List 14-2, 14-3 

CRST/WRST A-5, A-6, A-7 

CTRL_RTM A-127 

Cycle 4-3 

Cyclic Interrupt 

Rules 4-28 

Starting 4-28 

Cyclic Interrupt Organization Blocks (OB30 

to OB38) 4-28 

Cyclic Interrupts 4-28, 4-29 

Cyclic Program Execution 4-2 

D 

Data Block 

Shared 4-22 


Data Block (DB) A-29 

Instance Data Blocks 4-19 


Data Block Register A-26 

Data Blocks 11-1, 12-1 

Assigning Parameters to 12-1 

Basic Information 11-1 

Data View 11-3 

Declaration View 11-2 

Editing Data Values in the 

Data View 11-9 

Format Table 13-13 

Resetting Data Values to their Initial 

Values 11-9 

Saving 11-10 

Data Blocks (DB) 


Data Blocks in STL Source Files 13-27 

Example 13-27, 13-28 

Data Carrier 6-24 

Data exchange 

in different operating modes A-13 

Data Record 

Accessing A-119, A-121 

Reading A-119 

Writing A-119 

Data Storage 6-24 

Data Type 9-12 

DINT A-34 

DWORD A-39 

INT A-34 

S5TIME A-40 

User-Defined 9-12 

WORD A-39 

Data Types A-32, A-61, A-62 

ARRAY A-41 

BOOL A-33 

BYTE A-33 

Complex A-41 

DATE_AND_TIME A-41, A-42 

Description A-33 

Double Word (DWORD) A-33 

Elementary A-33 

FB 

SFB 4-16, A-41 

REAL A-35 

STRING A-41 

STRUCT A-41 

UDT A-41 

User Defined A-41 

Word (WORD) A-33 

Data Values 11-9 

Editing in the Data View of Data Blocks 

11-9 

Resetting to their Initial Values 11-9 

Data View of Data Blocks 11-3 

DATE_AND_TIME A-41, A-42, A-43, A-44 

Daylight saving time 18-9 

DB 4-22 

Deactivating 

Time-of-Day Interrupt 4-25 

Debugging STL Source Files 13-19 

Declaration View of Data Blocks 11-2 

Declaring Local Variables A-90 

Index-4 


A5E00706944-01

Index 

OB for the Sample Industrial Blending 


Declaring Parameters A-88 

FC for the Sample Industrial Blending 


DeclaringLocal Data A-64 

Default Settings for the LAD/STL/FBD 

Program Editor 10-4 

Defective 

CPU Operating Mode A-1 

Defining 8-14 

Symbols when Programming 8-14 

the Trigger for Modifying Variables 20-17 

the Trigger for 

Monitoring Variables 20-14 

Defining Logic Blocks A-79 

Delayed Processing of Interrupts and 

Asynchronous Errors A-116 

Example A-116 

Delaying 

Start Events 4-36 

Deleting 

S7 Blocks on the Programmable 


STEP 7 Objects 5-24 

Deleting Associated Values 16-31 

Describing the Individual Functional Areas 

3-4 

Describing the Operator Console 


3-9 

Describing the Required Operator Displays 

and Controls 3-9 

Detailed Comparison 9-18 

Detectable Errors 23-26 

Determining the Cause of a STOP 23-15 

Diagnosing Hardware 

Detailed Diagnostic View 23-8 

Quick View 23-5 

Diagnostic Buffer A-27, A-28 

Contents 23-23, A-27, A-28 

Definition A-27 

Displaying A-28 

Evaluating A-27 

Reading 23-18 

Diagnostic Data on Modules 23-21 

Diagnostic Event 23-23, A-27 

Diagnostic Functions 23-23 

Diagnostic Interrupt (OB82) 23-37 

Diagnostic Interrupt Organization Block 

23-37, 23-39 

Diagnostic Message 

Sending to Nodes 23-22 

Writing Your Own 23-22 

Diagnostic Status Data 23-21 

Diagnostics Symbols 23-3 

in the Online View 23-3 

Dialog Boxes 5-23 

Differences Between Project-Oriented and 

CPU-Oriented Assignment of Message 

Numbers 16-11 

Differences Between Saving and 

Downloading Blocks 19-2 

DINT A-33, A-34 

Direct Data Exchange (Lateral 

Communication) 7-3 

DIS_AIRT 4-36 

DIS_IRT 4-36 

Disabling Interrupts and Asynchronous 

Errors A-115 

Example A-115 

Display Language 16-32 

Display Options 

for CPU Messages and User-Defined 

Diagnostic Messages 16-39 

Displaying 

Addresses Without Symbols 14-10 

Block Information for LAD 

FBD 

and STL 14-9 

Block Lengths 9-15 

Data Structure of Data Blocks 

Referencing an (Instance DBs) 11-5 

Deleted Blocks 14-5 

Lists in Additional 

Working Windows 14-10 

Maximum Local Data Requirement in the 

Tree Structure 14-4 

Missing Symbols 14-10 

Module Information 23-2 

Program Structure 14-10 

Reference Data 14-10, 14-11 

Shared or Local Symbols 8-4 

Unused Addresses 14-10 

Displaying Accessible Nodes 18-2 

Displaying CPU Messages and 

User-Defined Diagnostic 

Messages 16-39 

Displaying Modules Configured with Later 

STEP 7 Versions or 

Optional Packages 7-6 

Displaying Stored CPU Messages 16-42 

Displaying the Operating Mode 18-8 

Distributed I/O 7-1, 7-3 

Distribution of the Memory Areas A-15 

Dividing a Process into Tasks and Areas 

for Example of Industrial Blending 

Process 3-2 

Dividing the Process into Tasks 

and Areas 3-2 

DMSK_FLT 4-36 

Documentation 1-1, 1-4, 5-6, 5-8, 24-1 

Double Integer (32 Bit) A-34 

Double Word (DWORD) A-33 


A5E00706944-01 

Index-5

Index 

Area A-33 

Download Methods Dependent on the Load 

Memory 19-4 

Download Objects 19-11 

Downloaded Blocks 

Saving on Integrated EPROM 19-7 

Downloading 19-9, 19-10, A-17 


Several Objects (see Compiling and 

Downloading Objects) 19-9 

User Program A-16 

User Programs 19-3 

Without Project Management 19-6 

Downloading via EPROM Memory Cards 

19-7 

Downward Compatibility 7-3 

DP Slaves 7-1, 7-2 

DP slaves with missing or faulty GSD files 

A-74 

DP Standard Slaves A-120 

DP/PA-Link (IM 157) 23-13 

DPNRM_DG A-120 

DPRD_DAT A-120 

DPWR_DAT A-120 

Dummy slave A-74 

DWORD A-33, A-39 

E 

Editing 8-14 

Data Values in the Data View of Data 

Blocks 11-9 

S7 Source Files 13-14 

the Symbol Table 8-14 

Uploaded Blocks 

if the User Program is Not on the 

PG/PC 19-17 

if the User Program is on the PG/PC 

19-17 

Editing Areas in Symbol Tables 8-21 

Editing Current Configurations with 

Previous Versions of STEP 7 7-3 

Editing Libraries (Version 2) 7-1 

Editing Projects(Version 2) 7-1 

Editing Symbol Tables 8-21 

Editing Symbols Across Multiple Networks 

26-2 

Editing Uploaded Blocks in the 

PG/PC 19-16 

Editor 

Settings for STL 10-4 

Elementary Data Types A-33 

Elements in Dialog Boxes 5-23 

EN_AIRT 4-36 

EN_IRT 4-36 

Enabling Interrupts and Asynchronous 

Errors A-115 

Example A-115 

Engineering Tools 1-14 

Entering 11-5 

Block Comments and Network 

Comments 10-16 

Data Structure of Data Blocks 

Referencing an FB 

(Instance DBs) 11-5 

Data Structure of User-Defined Data 

Types (UDT) 11-7 

Multiple Instance in the Variable 

Declaration Window 10-11 

Shared Symbols in a Program 10-14 

Single Shared Symbols in a 

Dialog Box 8-14 

Entering and Displaying the Data Structure 

of Data Blocks Referencing an FB 

(Instance DBs) 11-5 

Entering and Displaying the Structure of 

Data Blocks Referencing a UDT 11-8 

Entering Multiple Shared Symbols in the 


Entering Shared Symbols 8-13 

Entering Symbols 8-15 

Entering the Data Structure of Shared Data 

Blocks 11-4 

EPROM A-29 

EPROM Area A-16 

Erasing 19-18 

Load/Work Memory 19-18 

Erasing the Load/Work Memory and 

Resetting the CPU 19-18 

Error Detection 

OB Types 

OB81 23-26 

Sample Programs 

Substitute Values 23-31 

Using Error OBs to React to Errors 4-35 

Error Handling Organization Blocks (OB70 

to OB87 / OB121 to OB122) 4-35 

Error OB 23-26, 23-27, 23-28 

OB Types 

OB121 and OB122 4-35 

OB70 and OB72 4-35 

OB80 to OB87 4-35 

Using Error OBs to React to Events 4-35 

Error OBs 4-35, 4-36 

Error OBs as a Reaction to Detected Errors 

23-26 

Error Search 

in Blocks 10-18 

Errors (see Compiling and Downloading 

Objects) 19-11 

Establish 

Online Connections 18-1 

Index-6 


A5E00706944-01

Index 

Establishing 

Online Connection via the "Accessible 

Nodes" Window 18-2 

Online Connection via the Online Window 

of the Project 18-3 

Establishing a Connection 

to the CPU 20-13 

Establishing the Safety Requirements 3-8 

Evaluating the Diagnostic Buffer A-27 

Evaluating the Output Parameter 

RET_VAL 23-25 

Example 13-22 

Entering a Contiguous 

Address Area 20-10 

Entering Addresses in Variable Tables 

20-9 

for Disabling and Enabling Interrupts and 

Asynchronous Errors (SFC39 and 

SFC40) A-115 

for Masking and Unmasking 

Synchronous Errors A-110 

for the Delayed Processing of Interrupts 

and Asynchronous Errors (SFC41 and 

SFC42) A-116 

of Data Blocks in 


of Function Blocks in STL Source Files 

13-25 

of Functions in STL Source Files 13-23 

of Handling Time-of-Day Interrupts A-96 

of Organization Blocks in STL Source 

Files 13-22 

of User-Defined Data Types in STL 


Example of Working with Address 

Locations 14-13 

Examples 20-11 

Entering Modify and Force Values 20-11 

of Declaring Variables in STL Source 

Files 13-21 

Exceeding the L Stack A-24 

Exchanging Modules 26-1 

Exchanging Modules in the Configuration 

Table 26-1 

Expanding DP Slaves (Created with 

Previous Versions of STEP 7) 7-1 

Export file 6-17, 6-18 

Exporting 



Extended Uses of the STEP 7 Standard 

Package 1-13 

F 

Faults 

Locating 23-1 

FB 4-16, 4-17, 4-18, A-41 

FBD 9-5 

Displaying Block Information 14-9 

Rules 10-24 

FBD Elements 10-24 

Representation 10-23 

Rules for Entering 10-24 

FBD Layout 10-23 

FC 4-15, 4-16 

FC12 A-98 

FEPROM A-29 

File Formats for Importing/Exporting a 


Filtering Symbols 8-15 

Finding Address Locations in the Program 

Quickly 14-12 

Finding Nodes on the Subnet 18-2 

Firmware Update A-124 

Flash-File System 2-8 

Flashing Test 18-2 

Floating-Point Numbers A-35, A-36, A-37 

Flow 

of Diagnostic Information 23-18 

Folder 9-11 

Blocks 9-11 

for the CPU 16-11 

for the project 16-11 

FORCE LED Flashing 18-2 

Force Values 20-11 

Examples of Entering 20-11 

Forcing Variables 20-20 

Introduction 20-20 

Safety Measures 20-19 

Formal Parameters 

System Attributes 

and Message Blocks 16-8 

Format 

BLOCK A-53 

COUNTER A-53 

TIMER A-53 

Format of the Data Type DATE_AND_TIME 

A-42 

Format of the Data Type DINT (32-Bit 

Integers) A-34 

Format of the Data Type INT (16-Bit 

Integers) A-34 

Format of the Data Type REAL (Floating- 

Point Numbers) A-35 

Format of the Data Type S5TIME (Time 

Duration) A-40 


A5E00706944-01 

Index-7

Index 

Format of the Data Types WORD and 

DWORD in Binary Coded Decimal 

Numbers A-39 

Format of the Parameter Type ANY A-58 

Format of the Parameter Type POINTER 

A-53 

Format of the Parameter Types BLOCK 

COUNTER 

TIMER A-53 

Format Table of Data Blocks 13-13 

Format Table of Function Blocks 13-11 

Format Table of Functions 13-12 

Format Table of Organization Blocks 13-10 

Formats for Blocks in 


Function 

Correcting the Interface 15-6 

Function (FC) A-88 



Function Block (FB) A-83 

Function Block Diagram 9-5 

Function Block Diagram Programming 

Language (FBD) 9-5 

Function Block Diagram(FBD) 9-2 

Function Blocks 13-11 


Function Blocks (FB) 4-16 

Actual Parameters 4-17, 4-18 

Application 4-16 

Function Blocks in STL Source Files 13-25 

Example 13-25 

Functional Scope of Report System Errors 

16-45 

Functions 24-2 


Functions (FC) 4-15 


Functions in STL Source Files 13-23 

Example 13-23, 13-24 

G 

Gaps in the User Memory (RAM) 19-20 

GD Communication A-74 

General Tips 

on Entering Symbols 8-13 

Generating 

Reference Data 14-11 

STL Source Files from Blocks 13-17 

Generating and Displaying Reference Data 

14-11 

Generating Blocks for Reporting System 

Errors 16-49 

Global Data Communication A-74 

Global Symbols 

Entering in a Program 10-14 

GSD file A-74 

Guidelines 

Handling License Keys 2-5 

Guidelines for Handling License Keys 2-5 

H 

Handling Errors 23-25 

Handling Large Projects 26-1 

Hardware Diagnostics and Troubleshooting 

23-1 

Hardware Interrupt 4-30 

Priority 4-30 

Rules 4-30 

Starting 4-30 

Hardware Interrupt Organization Blocks 

(OB40 to OB47) 4-30 

Hardware Interrupts 4-30 

Headers and Footers 24-3 

Help (Online) 

Calling 5-5 

Topics 5-5 

Hierarchical Structure of Libraries 9-22 

HiGraph 9-3 

HOLD 


HOLD Mode A-14 

Hot Restart A-5, A-6, A-7, A-8, A-9, A-10 

Abort A-5 

Automatic A-6, A-7 

Manual A-5, A-6 

How to Assign and Edit Symbol-Related 

Messages (CPU-Oriented) 16-26 

How to Assign and Edit Symbol-Related 

Messages (Project-Oriented) 16-18 

How to Assign CPU-Oriented Message 

Numbers 16-20 

How to Assign Project-Oriented Message 

Numbers 16-12 

How to Configure PCS 7 Messages (CPU- 

Oriented) 16-25 

How to Configure PCS 7 Messages 

(Project-Oriented) 16-16 

How to Create Block-Related Messages 

(CPU-Oriented) 16-21 

How to Edit Block-Related Messages 


How to Edit Block-Related Messages 


Human Machine Interface 1-18 

Index-8 


A5E00706944-01

Index 

I 

I Stack 

Description A-25 

I/O 

Address Areas A-117 

I/O Access Error (OB122) 23-44 

I/O Access Error (PZF) during Update of 

the Process Image A-20 

I/O Access Error Organization Block 23-44 

I/O Data A-118 

I/O Redundancy Error (OB70) 23-33 

I/O Redundancy Error Organization Block 

23-33, 23-34 

Icon for unknown modules 7-6 

Icons for Objects in the 

SIMATIC Manager 5-6 

ID Number 

Entering 2-8 

Identifying Nodes Directly Connected to a 

Programming Device/PG 18-2 

Illegal Logic Operations in Ladder 10-22 

IM 157 (DP/PA link) 23-13 

Importing 

External Source File 6-12 



IN (Variable Declaration) A-64 

In/out Parameters A-64, A-65 

IN_OUT (Variable Declaration) A-64 

IN_OUT Parameters of a 

Function Block A-71 

Incompatibility A-74 

Incomplete and Non-Unique Symbols in the 


Indirect Parameter Assignment A-121 

Industrial Blending Process A-83, A-88, 

A-90 

Information Functions 23-12 

Information Functions in the 

Diagnostic View 23-8 

Information Functions in the 

Quick View 23-5 

Information on the Log File 6-19 

Input Parameters A-64 

Inputs 

Assignment List 14-6 

Process Image A-20 

Insert/Remove Module Interrupt (OB83) 

23-38 

Insert/Remove Module Interrupt 

Organization Block 23-38 

Inserting 

Addresses or Symbols in a 


Block Templates in 


Comment Lines 20-9 

Contents of Other 


Modify Values 20-7 

Source Code from Existing Blocks in 


Substitute Values for 

Error Detection 23-31 

Inserting a Contiguous Address Range in a 


Inserting an S7/M7 Program 6-12 

Inserting Block Templates in STL Source 

Files 13-15 

Inserting External Source Files 13-16 

Inserting Program Elements 10-5 

Inserting Source Code from Existing Blocks 

in STL Source Files 13-16 

Inserting Stations 6-11 

Installation Errors 2-8 

Installation Procedure 2-8 

Installation Requirements 2-6 

Installing 

STEP 7 2-6, 2-7 

Installing STEP 7 2-6 

Installing the Automation License Manager 

2-4 

Instance 4-19, 4-20, 4-21 

Instance Data Block A-29 



Creating Multiple Instances 

for an FB 4-16 

Time Stamps 15-5 

Instance DB 4-19, 4-20, 4-21 

Instruction List 10-8 

Instructions from the Program Elements 

Table 10-5 

INT A-33, A-34 

Integer (16 Bit) A-34 

Interaction Between The Variable Detail 

View And The Instruction List 10-8 

Interrupt Assignments 

Checking 2-11 

Interrupt Stack A-15, A-25 

Interrupt-Driven Program Execution 4-2 

Interruption Time A-10 

Interrupts A-115, A-116 

Delayed Processing A-116 

Disabling and Enabling A-115 

Introduction A-32 

Introduction to Data Types and Parameter 

Types A-32 

Introduction to Forcing Variables 20-20 

Introduction to Testing with the Variable 

Table 20-1 


A5E00706944-01 

Index-9

Index 

K 

k7e 6-25 

k7p 6-25 

Key Combinations 

for Access to Online Help 5-36 

for Menu Commands 5-33 

for Moving the Cursor 5-34 

for Selecting Text 5-36 

Key Combinations for Toggling between 

Windows 5-37 

Keyboard Control 5-32 

L 

L Stack A-24 

Assigning Memory to 

Local Variables A-24 

Overwriting A-24 

Storing Temporary Variables 4-16 

LAD 9-4 


Ladder Elements 


Ladder Layout 10-19 

Ladder Logic 9-4 

Guidelines 10-19 

Ladder Logic (LAD) 9-2 

Ladder Logic Programming Language 

(LAD) 9-4 

Language 

for Display 16-32 

Language Editors 

Starting 9-2 

Large Projects 26-1 

Lateral Communication 7-3 

Libraries 6-13 

Archiving 24-4 

Hierarchical Structure 9-22 

Rearranging 26-2 

Working with 9-20 

Library 5-9 

Library Object 5-9 

License 2-1, 2-2, 2-3 

License Key 2-1, 2-2, 2-3 

License Keys 2-5 

License Manager 2-1, 2-2 

Linear Programming 4-2 

List Box 5-23 

Listing In/Outs 3-6 

Listing Inputs 3-6 

Outputs 

and In/Outs 3-6 

Listing Outputs 3-6 

Lists 

of Operator Related Texts 16-32 

Load Memory 19-3, 19-4, A-15, A-16 

Load Memory and Work Memory A-16 

Load Memory and Work Memory in the 

CPU 19-3 

Local Data Requirements 14-4 

Local Data Stack A-15, A-24, A-25 

Local time 18-9 

Locating Faults 23-1 

Logic Blocks A-79 

in the Incremental Editor 10-3 

Saving 10-29 



M 

M7 Program 6-13 

M7 Programming 

Optional Software 25-3, 25-4 

M7-300/M7-400 

Operating Systems 25-1 

M7-300/M7-400 Operating Systems 25-6 

Make (see Checking Block Consistency) 

15-1 

Managing 

Objects 5-24, 5-25, 5-26, 5-27, 5-28 

Managing Multilingual Texts 6-14 

Managing User Texts Whose Language 

Font is Not Installed 6-18 

Masking 


Masking Synchronous Errors A-110 

Example A-110 

Memory A-31 

Configurable A-31 

Memory Area A-29 

Memory Area 

Retentive A-29, A-30 

Memory Areas A-15 

Address Areas A-18 

Load Memory A-15 

Retentive A-29, A-30 

Special Features with S7-300 A-16 

Special Features with S7-400 A-16 

System Memory A-15 

Work Memory A-15 

Memory bit 


Memory Card A-17 

Assigning Parameters 2-9 

Memory Card file 6-24 

Memory Reset A-4 

Message 

Example 16-6 

Parts 16-5 

Message Blocks 

Overview 16-6 

Message Configuration 

SIMATIC Components 16-5 

Index-10 


A5E00706944-01

Index 

Transferring Data to WinCC 16-38 

Message number assignment 16-11 

Message Numbering 16-2 

Message Numbers 16-11 

Message Type 16-9, 16-10 

Message Type and Messages 16-9 

Messages (CPU-Oriented) 

symbol-related 16-26 

Messages (Project-Oriented) 

symbol-related 16-18 

Message-type Block 16-14, 16-22 

Messaging Numbers 16-10 

Assigning 16-10 

Micro Memory Card (MMC) 6-24, 6-25 

Micro Memory Cards (MMC) 6-22 

MMC 6-22, 6-23, 6-24, 6-25 

Mnemonics 

Setting 10-26 

Mode Transitions A-2, A-3 

Modify Values 20-11 

Examples of Entering 20-11 


Modifying 

Basic Procedure 20-2 

Modifying Variables 


Modifying Variables With the Program 

Editor 26-4 

Module 22-1 


Module Exists/Type Monitoring 

Startup OBs 4-31 

Module icon for unknown modules 7-6 

Module Information 23-7, 23-13 

Calling from the Project View (Online) 

23-6 


Displaying for PA Field Devices 23-13 

Displaying for PA Field Devices After a Y- 

Link 23-13 

Options for Displaying 23-9 

Updating 23-11 

Module Information Functions 23-10 

Module Parameters A-121, A-122, A-123 

Transferring with SFCs A-121 

Transferring with STEP 7 A-121 

Module Start Address A-117 

Module Status 23-12 

Information Functions 23-10 

Module Time 18-9, 18-10 

Modules 26-1 

Exchanging 26-1 

Parameter Assignment A-121, A-123 

Monitoring 


Monitoring Times 4-32 

Monitoring Variables 20-14 

Defining theTrigger 20-14 


Motors 3-6 

Creating an I/O Diagram 3-6 

Moving 

Object 5-24, 5-25, 5-26, 5-27, 5-28 

MPI Card for PG/PC 2-11 

MPI FW Update 18-10 

MPI Interface 2-6, 2-7 

MPI-ISA Card (Auto) 2-11 

MSK_FLT 4-36 

Multiple Instance 4-16 

entering in the Variable Declaration 

Window 10-11 

Multiple instances 

Use 10-10 

Multiple Instances 4-21 

Rules 10-11 

Multiproject 

Online Access to PLCs in 18-4 

N 

Naming Conventions 17-2 

for Configuration Data 17-1 

Nested Calls of Logic Blocks A-26 

Effects on the B Stack and L Stack A-26 

Nesting A-26 

Nesting Depth 4-8 

Network Comment 10-15 

Network Comments 

Entering 10-16 

Network Templates 

Working with 10-17 

Network Title 10-15 

Networks 9-5 


Non-Retain 9-14 

Non-Volatile RAM A-29 

Notes on STEP 7 V.2.1 Projects with GD 


Number Notation A-32 

NVRAM A-29, A-30 

O 

OB 4-2, 4-3, 4-4, 4-5, 4-6 

OB1 A-90, A-91, A-92, A-108 

OB1 and OB80 A-102 

OB10 A-100, A-101 

OB100 A-5 

OB101 A-5, A-12 

OB102 A-5 

OB121 23-43 

OB122 23-44 

OB20 A-106 

OB70 23-33 

OB72 23-34 


A5E00706944-01 

Index-11

Index 

OB80 23-35 

OB81 23-36 

OB82 23-37 

OB83 23-38 

OB84 23-39 

OB85 23-40, A-23 

OB86 23-41 

OB87 23-42 

Object 

Cutting 

Copying 

Pasting 5-26 

Deleting 5-28 

Moving 5-27 

Opening 5-25 

Properties 5-25, 5-26, 5-27 

Renaming 5-26, 5-27 

Selecting 5-29 

Object Hierarchy 5-6 

Building 5-25 

Objects 5-6, 5-7 

as Carriers of Functions 5-7 

as Carriers of Properties 5-6 

as Folders 5-6 

Managing 5-24 

Objects and Object Hierarchy 5-6 

Offline Updating of the Firmware in 

Modules and Submodules A-124 

Offset factor 18-9 

Online Access to PLCs in a Multiproject 

18-4 

Online Connection 

Establishing via the "Accessible Nodes" 

Window 18-2 

Establishing via the Online Window of the 

Project 18-3 

Online Connection by Means of DP 

Interface 7-3 

Online Connections 

Establish 18-1 

Online Help 

Calling 5-5 

Changing the Font Size 5-5 

Topics 5-5 

Online Updating of Firmware in Modules 

and Submodules 18-10 

Online View 23-3 

Diagnostic Symbols 23-4 

Opening 



Operating Mode A-2, A-3 

Displaying and Changing 18-8 

HOLD A-1, A-2, A-3 

RUN A-1, A-2, A-3 

STARTUP A-5 

STARTUP A-1, A-2, A-3 

STOP A-4 

Operating Mode STOP 23-15 

Stack Contents 23-15, 23-16 

Operating Modes 

Priority A-3 

Operating Modes and 

Mode Transitions A-1 

Operating Philosophy 5-21 


Tasks 4-1 

Operator Console 3-9 

Operator Control and Monitoring Attributes 

17-1 

CFC 17-5 

Configuring with STL 

LAD 

FBD 17-3 

Configuring with Symbol Table 17-4 

Operator Displays and Controls 


3-9 

Operator Related Texts 

Exporting/Importing 16-32 


Optimizing the Source for Translation 6-20 

Optimizing the Translation Process 6-21 

Optional Package 22-1 

Optional Software for 

M7 Programming 25-4 

Options for Displaying the Module 

Information 23-9 

Options for Modifiying the Message 

Number Assignment of a Project 16-11 

Organization Block (OB) 4-33 

Background OB (OB90) 4-2 

Organization Blocks 13-10 

Creating an OB for the Sample Industrial 


Definition 4-2 

Error Detection 

OB122 



Priority Classes 4-2, 4-4, 4-5 

Reacting to Errors 4-35 

Organization Blocks and 

Program Structure 4-2 

Organization Blocks in 

STL Source File 13-22 

Example 13-22 

OUT (Variable Declaration) A-64 

Output Parameter 23-25, 23-26 

Evaluating RET_VAL 23-25 

Output Parameters A-64 

Outputs 



Index-12 


A5E00706944-01

Index 

Overview 1-4, 14-1, 16-6 

Message Blocks 16-6 

of the Available Reference Data 14-1 

Overview of STEP 7 1-1 

Overview of the Available Reference Data 

14-1 

Overview of the Standard Libraries 9-22 

Overwrite Mode 10-18 

Overwriting the L Stack A-24 

P 

PA Field Devices 23-13 

Page Format 

Setting 24-3 

Parameter Assignment A-126 

Clock A-126 

Indirect A-121 

with SFCs A-123 

with STEP 7 A-123 

Parameter Type POINTER 

Using A-54 

Parameter Types A-52, A-61 

Parameters 9-19 

Attributes 9-19 

Parent/Child Structure 14-4 

PARM_MOD A-119, A-123 

Part Process Image (Process Image 

Partition) A-20 

System Update A-22 

Updating with SFCs A-20 

Parts of a Message 16-5 

Password 18-6 

Password Protection for Access to 

Programmable Controllers 18-6 

PC Station 7-4, 7-5 

Peripheral Data A-118 

Permitted Block Properties for Each Block 

Type 13-7 

Permitted Data Types when Transferring 

Parameters A-66 

PG/PC Interface 2-11 

Parameter Assignment 2-11 

Phase Offset 4-29 

Planning an Automation Project 



Creating an I/O Diagram 


Creating an I/O Diagram 


Describing the 

Individual Function Areas 3-4 

Describing the Required Operator 

Displays and Controls 3-9 

Dividing the Process into Tasks and 

Areas 3-2 

Establishing the 

Safety Requirements 3-8 

Listing Inputs 

Outputs 

and In/Outs 3-6 

Pointer A-54, A-55, A-56, A-57 

POINTER A-52, A-53, A-54 

Positioning 

Boxes 10-24, 10-25 

Power Failure A-5 

Power Flow 10-22 

Power Supply Error (OB81) 23-36 

Power Supply Error 


Preventing Personal Injury 20-20 

Preventing Property Damage 20-20 

Printer 

Setting Up 24-2 

Printing 

Blocks 24-1 

Configuration Table 24-1 

Diagnostic Buffer Content 24-1 

Global Data Table 24-1 




Printing Project Documentation 24-1 

Priority 

Background OB 4-33 


Time-Delay Interrupt 4-27 


Priority (Symbolic/Absolute Address) 8-5 


for Archiving/Retrieving 24-6 

for Entering Statements 10-13 

for M7 Systems 25-1 

Process 

Dividing into Tasks 3-2 

Process control dialog 

see How to Configure of PCS 7 

Messages (CPU-Oriented) 16-25 

Process Control Dialog 

see How to Configure PCS 7 Messages 



Clearing 4-32 

Inputs/Outputs A-20 

Process Monitoring 17-1, 20-2 

PROFIBUS 18-11, 18-12 

PROFIBUS DP 7-2 

PROFIBUS PA Devices 23-13 

PROFIBUS-DP 7-3 

PROFINET Nodes 18-2 

Program Creation 

General Procedure 1-1 

Program Editor 9-16, 9-17, 9-18, 10-1 


A5E00706944-01 

Index-13

Index 

Program Execution 

Cyclic 4-2, 4-4, 4-5, 4-6 

Interrupt-Driven 4-2 

Program Measures for 

Handling Errors 23-24 

Program Sequence Error (OB85) 23-40 

Program Sequence Error Organization 

Block 23-40 

Program Status 

Setting the Display 21-7 

Testing with 21-1 

Program Status Display 21-2 

Program Status of Data Blocks 21-6 

Program Structure 14-4, 14-5 


Programmable Controller 

Reloading Blocks 19-6 

Programmable Module Object Folder 5-12 


Background OB 4-33 

Transferring Parameters 4-16 

Using Data Blocks 4-16 

Programming Error (OB121) 23-43 

Programming Error 


Programming Language 

S7-GRAPH (Sequential Control) 9-8 

Selecting 9-2 

Programming Languages 1-6, 1-9 

Function Block Diagram (FBD) 9-5 

Ladder Logic (LAD) 9-4 

S7 CFC 9-10 

S7 HiGraph 9-9 

S7 SCL 9-7 

STL 9-6 

Programming Steps 

S7 1-4 

Programs in a CPU 4-1 

Project 5-8, 5-9 

Creating Manually 6-9 

Creating Using the Wizard 6-9 

Project Documentation 

Printing 24-1 

Project Language 6-5, 6-6, 6-7 

Project Object 5-8 

Project Structure 6-2 

Project View 6-2 

Project Window 6-1, 6-2 

Project-Oriented 16-11 

Projects 24-4 


Rearranging 26-2 

Renaming 5-24 

Projects with a Large Number of Networked 

Stations 26-1 

PZF (I/O Access Error) A-20 

Q 

QRY_TINT 4-26 

Querying 


Quick View of the 

Diagnostic Information 23-5 

R 

Rack Failure (OB86) 23-41 

Rack Failure Organization Block 23-41 

RAM A-15, A-29 

RAM Area A-16, A-30 

RDSYSST 23-18, 23-20, A-28 

READ_CLK A-126 

READ_RTM A-126 

Reading and Adjusting the TOD and the 

TOD Status 18-9 

Reading from a Data Block in 


REAL A-33, A-35 

Rearranging Projects and Libraries 26-2 

Redundant Mode 18-12 



Displaying 14-10, 14-11 

Generating 14-11 

Reloading Blocks in the Programmable 


Remaining Cycle A-6, A-9, A-10 

Renaming A-74 

Projects 5-24, 5-26 

STEP 7 V.2.1 Projects with Global Data 


Report System Errors 16-45 

Supported Components 16-45 

Reporting System Errors 16-43, 16-49 

Representation 

FBD Elements 10-23 

Ladder Elements 10-19 

STL 10-26 

Representation of unknown modules 7-6 

Representative modules 7-6 



for Downloading 19-1 

Requirements for and Notes on 

Downloading 19-9 

Resetting 11-9 

Data Values to their Initial Values 11-9 

the CPU 19-18 

Restoring 

Window Arrangement 5-31 


A-29 


A-30 

Index-14 


A5E00706944-01

Index 

Retentivity 

on Power Failure A-5 

Retrieving 


Rewiring 9-19 

Addresses 9-19 

Blocks 9-19 

Ring Buffer (Diagnostic Buffer) A-27 

RPL_VAL 23-31 

Rules 8-18 

Cyclic Interrupt 4-28 

FBD 10-24 

for Block Order in STL Source Files 13-4 

for Declaring Multiple Instances 10-11 

for Declaring Variables in STL Source 

Files 13-3 

for Exporting the Symbol Table 8-18 

for Importing the Symbol Table 8-18 

for Setting Block Properties in STL 


for Setting System Attributes in STL 




Statement List 10-26 


Time-of Day-Interrupt 4-25 

Rules for Entering FBD Elements 10-24 

Rules for Entering Ladder Logic Elements 

10-19 

Rules for Entering STL Statements 10-26 

RUN 

CPU Activities A-5 


RUN Mode A-13 

Run-Time Meter A-126 

Run-Time Software 1-16 

S 

S5 TIME A-33 

S5TIME A-40 

S7 CFC Programming Language 9-10 

S7 Export File 6-25 

S7 HiGraph 9-9 

S7 HiGraph Programming Language (State 

Graph) 9-9 

S7 Program 


S7 SCL Programming Language 9-7 

S7 Source Files 13-14 

Editing 13-14 

S7/M7 Program 5-14 

S7/M7 Program Folder 5-14 

S7/M7 Program without a Station or CPU 

5-20 

S7-GRAPH 9-2, 9-8 

S7-Routing 18-10 

Safety Measures When Forcing Variables 

20-19 

Safety Notes A-24 




Example of an Industrial Blending 

Process 3-8 

Sample Program A-79, A-81, A-86, A-88, 

A-90, A-91, A-110, A-115, A-116 

Sample Program for an Industrial Blending 


Sample Programs A-75, A-83 

FB for the Industrial 


FC for an Industrial 


Industrial Blending Process A-77 


Describing the Individual Functional 

Tasks and Areas 3-4 

Describing the Individual Tasks and 

Areas 


Describing the Operator Displays and 

Controls 3-9 

Describing the 


Dividing the Process into Tasks and 

Areas 3-2 

Inserting Substitute Values 23-31 



Reaction to Battery Error 23-26 


Sample Projects A-75, A-76 

Save as 6-25 

Saving 

Blocks 10-29 

Data Blocks 11-10 

Downloaded Blocks on Integrated 

EPROM 19-7 

Logic Blocks 10-29 


Uses 24-5 



SCAN Message 

see Symbol-Related Messages (Project- 


SCAN messages (CPU-Oriented) 

see Symbol-Related Message 16-26 

SCL 9-2, 9-7 

Scope of the Module Type-Dependent 

Information 23-12 

sdf 6-25 


A5E00706944-01 

Index-15

Index 

Search Function for Errors in the Code 

Section 10-18 

Selecting 

Editing Method 9-1 

Programming Language 9-2 

Selecting Objects in a Browser 5-29 

Sending 

Your Own Diagnostic Messages 23-22 

Session Memory 5-30 

SET_CLK 4-26, A-126 

SET_CLKS 18-9 

SET_RTM A-126 

SET_TINT 4-25, 4-26 

Setting 

Operating Behavior A-120 

Virtual Work Memory 26-5 

Setting the Address Priority 

(Symbolic/Absolute) 8-5 

Setting the Display for 

Program Status 21-7 

Setting The Layout of 

Source Code Text 13-15 

Setting The Layout of Source Code Text 

Code 13-15 

Setting the Mnemonics 10-26 

Setting the Mode for the Test 21-8 

Setting the MS Windows Language 6-8 

Setting the PG/PC Interface 2-11 

Settings for Function Block Diagram 

Programming 10-23 

Settings for 

Ladder Logic Programming 10-19 

Settings for Reporting System Errors 16-48 

Settings for Statement List Programming 

10-26 

Setup 

Entering ID Number 2-8 

Flash-File System 2-8 

Memory Card Parameters 2-9 

SFB 4-23, A-41 

SFB33 16-7 

SFB34 16-7 

SFB35 16-7 

SFB36 16-7 

SFB37 16-7 

SFC 4-23 

Using A-20 

SFC 13 DPNRM_DG A-120 

SFC 14 DPRD_DAT A-120 

SFC 15 DPWR_DAT A-120 

SFC 55 WR_PARM A-121 

SFC 56 WR_DPARM A-121 

SFC 57 PARM_MOD A-121 

SFC0 SET_CLK A-126 

SFC1 READ_CLK A-126 

SFC100 'SET_CLKS' 18-9 

SFC17/18 16-6 

SFC2 SET_RTM A-127 

SFC20 BLKMOV A-16 

SFC22 CREAT_DB A-16 

SFC26 UPDAT_PI A-20 

SFC27 UPDAT_PO A-20 

SFC28 SET_TINT 4-25, A-96 

Example in STL A-96 

SFC29 CAN_TINT 4-25, A-96 


SFC3 CTRL_RTM A-126 

SFC30 ACT_TINT 4-25, A-96 


SFC31 QRY_TINT 4-25, A-96 


SFC32 SRT_DINT 4-27 

SFC36 MSK_FLT 4-35 

Example in LAD A-110 


SFC37 DMSK_FLT 4-35 



SFC38 READ_ERR 



SFC39 DIS_IRT 4-35 


SFC4 READ_RTM A-127 

SFC40 EN_IRT 4-35 


SFC41 DIS_AIRT 4-35 


SFC42 EN_AIRT 4-35 


SFC44 RPL_VAL 23-31 

SFC48 SNC_RTCB A-126 

SFC51 RDSYSST 23-18, 23-19, A-27 

SFC52 WR_USMSG 23-22 

SFC55 WR_PARM A-118 

SFC56 WR_DPARM A-118 

SFC57 PARM_MOD A-118 

SFC82 6-22 

SFC83 6-22 

SFC84 6-22 

Shared and Local Symbols 8-3 

Shared Data Blocks 11-4 

Entering the Data Structure 11-4 


Shared Data Blocks (DB) 4-22 

Short Circuit 

Ladder Logic 

Illegal Logic Operations 10-22 

Signal Module 22-1 


Signal Modules with Hardware Interrupt 

Capability 

Assigning Parameters 4-30 

SIMATIC Components 16-5 

Index-16 


A5E00706944-01

Index 

SIMATIC Manager 5-1, 9-16, 9-18 

Displaying Block Lengths 9-15 

SIMATIC PC - Appending Configurations of 

Previous Versions 7-4 

SIMATIC PC Station 7-4 

Simulating a CPU or Signal Module 22-1 

Simulation Program 22-1 

Slaves with missing 

or faulty GSD files A-74 

SlotPLC 6-24 

SNC_RTCB A-126 

Software Packages 

Checking Projects for 6-14 

Software PLC 6-24 

Sorting in the Cross Reference List 14-2 

Sorting Symbols 8-15 

Source Code 13-15 

Source File Folder 5-19 

Source File Folder Object 5-19 



Exporting 13-18 

External 6-13 

Generating STL Source Files 

from Blocks 13-17 

Importing 13-17 

Inserting External Source Files 13-16 

Rules for Block Order in STL Source 

Files 13-4 

Rules for Declaring Variables in STL 


Rules for Entering Statements in STL 


Rules for Setting Block Properties in STL 


Rules for Setting System Attributes in 


Saving STL Source Files 13-19 

Source Files in S7-GRAPH 9-8 

Special Note on Printing the Object Tree 

24-3 

SRT_DINT 4-27 

SSL 23-19 

Stack Contents in STOP Mode 23-15 

Standard Libraries 9-22 

Overview 9-22 

Standard Library 6-12 

Start Address A-118 

Start Events 

Delaying 4-35 

Masking 4-36 


Starting 

Cyclic Interrupt 4-28, 4-29 



Time-of-Day Interrupt 4-25, 4-26 

Starting STEP 7 Installation 2-8 

Starting STEP 7 with Default Start 

Parameters 5-3 

STARTUP A-5, A-9, A-10, A-11, A-12 

Abort A-5 

CPU Activities A-5 


Startup OB A-5, A-9, A-10, A-12 


Module Exists/Type Monitoring 4-32 


Startup Organization Blocks (OB100 / 

OB101 / OB102) 4-31 

Startup Program 4-31 

STAT (Variable Declaration) A-64 

State Graph 9-9 

Statement List 9-6, 10-26 


Rules 10-26 

Statement List (STL) 9-2 

Statement List Programming Language 

(STL) 9-6 

Statements 

Entering 


Station 5-10, 5-11 


Uploading 19-15 

Station Object 5-10 

Status Bar 

Example 5-22 

STEP 7 1-6, 1-7, 1-9 

Error OBs 

Reacting to Errors 4-35 

Errors During Installation 2-8 

Installation 2-6, 2-7 

Removing 2-13 

Starting the Software 5-1 

Uninstalling 2-13 

User Interface 5-22 

STEP 7 

Programming Languages 1-6 

Standard Software 1-6 

STL 9-6 


Entering Blocks 10-13 

STL Editor 

Settings 10-4 

STL Source File 13-10 

Formats for Blocks 13-10 

STL source files 

Creating 13-14 


Basic Information on Programming 13-1 

Checking Consistency 13-19 

Compiling 13-20 

Debugging 13-19 


A5E00706944-01 

Index-17

Index 

Example of Data Blocks 13-27 

Example of Function 13-23 

Example of Function Blocks 13-25 

Example of Organization Blocks 13-22 

Example of User-Defined Data Types 

13-28 

Examples of Declaring Variables 13-21 

Generating from Blocks 13-17 

Inserting Block Templates 13-15 

Inserting External Source Files 

External Source Files 13-16 

Inserting Source Code from Existing 

Blocks 13-16 

Inserting the Contents of Other STL 


Rules for Block Order 13-4 

Rules for Declaring Variables 13-3 

Rules for Entering 

for Entering Statements in STL Source 

Files 13-2 

Rules for Setting Block Properties 13-5 

Rules for Setting System Attributes 13-4 

Saving 13-19 

Structure of Blocks 13-7 

Structure of Data Blocks 13-9 

Structure of Logic Blocks 13-8 

Structure of User-Defined Data Types 

13-9 

Syntax for Blocks 13-10 

STOP 


STOP Mode A-4 

Storing Project Data on a Micro Memory 

Card (MMC) 6-25 

STRING A-41, A-44 

STRUCT A-41, A-44, A-48 


Blocks in STL Source Files 13-7 

Cross-Reference List 14-2, 14-3 

Data Blocks in STL Source Files 13-9 

Load Memory A-16, A-17 

Logic Blocks in STL Source Files 13-8 

of the Code Section 10-12 

of the User Program "Time-of-Day 

Interrupts" A-96 

UDT 9-12 

User-Defined Data Type (UDT) 9-12 

User-Defined Data Types in STL Source 

Files 13-9 

Variable Declaration Window 10-9 

Structure and Components of the Symbol 

Table 8-9 

Structure of the export file 6-17 

Structure of the Program Editor Window 

10-1 

Structure of the User Program "Time-Delay 

Interrupts" A-104 

Structured Control Language 9-7 

Structured Data Types A-41 

Structured Programming 4-7 

Substitute Value 

Using SFC44 (RPL_VAL) 23-31 

Summer/winter time 18-9, 18-10 

Supported Components and Functional 

Scope 16-45 


File Formats for 

Importing/Exporting 8-18 

for Shared Symbols 8-9 

Opening 8-15 

Permitted Addresses 8-11 

Permitted Data Types 8-11 

Structure and Components 8-9 

Symbolic Addressing 8-4 

Sample Program A-81 

Symbolic Names A-81 

Assigning A-81 

Symbol-Related Messages (CPU-Oriented) 

Assignment to the Symbol Table 16-26 

Permitted signals 16-26 

Symbol-Related Messages (Project- 

Oriented) 

Assignment to the Symbol Table 16-18 

permitted Signals 16-18 

Symbols 8-1, 8-2, 8-4, 8-16 

Defining when Programming 8-14 

Entering 8-15 

Filtering 8-15 

for the Program Structure 14-4, 14-5 

Inserting in a Variable Table 20-4 

Local 8-3 

Shared 8-3 

Sorting 8-15 

STEP 7 Objects 5-6 

Unused 14-8 

Upper and Lower Case 8-16 

Symbols for Objects in the SIMATIC 

Manager 5-6 

Synchronizing A-126 

Clock A-126 

Synchronous Errors A-110 

Masking and Unmasking A-110 

Using OBs to React to Errors 4-35 

Syntax for Blocks in 


System Attributes 

for Configuration of PCS 7 Messages 


for configuring PCS 7 Messages (Project- 


for Message Configuration 16-8 

for Parameters 10-6 

in the Symbol Table 8-9, 8-10 

System Data 23-20 

Index-18 


A5E00706944-01

Index 

System Diagnostics 

Extending 23-22 

System Error 23-23 

System Function Blocks 4-23 

System Function Blocks (SFB) and System 

Functions (SFC) 4-23 

System Functions 4-23 

System Memory A-15, A-18 

System Parameters A-120 

System Status List 23-19, 23-20, 23-21 

Contents 23-19 

Reading 23-19 

System Text Libraries 16-36 

T 

Tabs in Dialog Boxes 5-23 

Tasks 

Example of Industrial 

Blending Process 3-2 

Tasks and Areas 


3-4 

TEMP (Variable Declaration) A-64 

Temporary Variables A-64, A-65 

Test 

Setting the Mode 21-8 

Testing 20-1 

Using Program Status 21-1 

using the Simulation Program (Optional 

Package) 22-1 

with the Variable Table 20-1 

Testing in Single-Step Mode 21-3, 21-4 

Testing with the Variable Table 26-3 

Text Libraries 16-36 

Translating 16-36 

Text Library 16-30, 16-31 

Integrating Texts into Messages 16-30 

Text Lists 

see Lists of User Texts 16-32 

The Message Concept 16-1 

The STEP 7 Standard Package 1-7 

Time A-33 

Reading A-126 

Setting A-126 

Time Error (OB80) 23-35 

Time Error Organization Block 23-35 

Time Format A-126 

TIME OF DAY A-33 

Time stamp 18-9 

Time Stamp Conflicts 15-3 


as a Block Property 15-3 

in Instance Data Blocks 15-5 

in Logic Blocks 15-4 

in Shared Data Blocks 15-5 

Time stamps in UDTs and Data Blocks 

Derived from UDTs 15-6 

Time Zones 18-9 

Time-Delay Interrupt 

Priority 4-27 

Rules 4-27 

Starting 4-27 

Time-Delay Interrupt Organization Blocks 

(OB20 to OB23) 4-27 

Time-Delay Interrupts 4-27 

Time-of-Day Interrupt 

Changing the Time 4-26 

Deactivating 4-26 

Priority 4-26 

Querying 4-26 

Rules 4-25 

Starting 4-25 

Time-of-Day Interrupt Organization Blocks 

(OB10 to OB17) 4-25 

Time-of-Day Interrupts 4-25 

Handling A-96 

Structure A-96 

TIMER A-52, A-53 

Timers 

Upper Limits for Entering 20-7 

Timers (T) A-128 

Memory Area 


Times 14-6 


Tips and Tricks 26-1, 26-2, 26-3, 26-5 

Title Bar 5-22 

Titles 

for Blocks 10-15 

for Networks 10-15 

TOD Interrupt 18-9 

TOD Status 18-10 

TOD Synchronization 18-10 

Toggling between Windows 5-37 

Toolbar 

Buttons 5-22 

Transferring Configuration Data to the 

Operator Interface Programmable 


Transferring Configuration Data to the 

Programmable Controller 16-38 

Transferring Parameters 

Saving the Transferred Values 4-16 

Transferring to IN_OUT Parameters of a 

Function Block A-71 

Translating and Editing 

Operator Related Texts 16-32 

Translating and Editing User Texts 16-32 

Tree Structure 14-4 

Trigger Frequency 20-14 

Trigger Point 

Setting 20-14 


A5E00706944-01 

Index-19

Index 

Troubleshooting 23-1 

Sample Programs 23-26 

Type File 7-1 

Types of Interrupt 4-2 

Types of Licenses 2-3 

Enterprise License 2-1 

Floating License 2-3 

Rental License 2-3 

Trial License 2-3 

Upgrade License 2-1 

Types of Multilingual Texts 6-16 

U 

UDT 9-12, A-41, A-50, A-51 

Uninstalling STEP 7 2-13 

Uninstalling the User Authorization 2-5 

Unmasking 


Unmasking Synchronous Errors A-110 

Example A-110 

Unused Addresses 


Unused Symbols 14-8 

UPDAT_PI A-20 

UPDAT_PO A-20 

Update (CPU Operating System) A-124 

Updating 18-13, A-124, A-125 

Firmware (of the Operating System) in 

Modules and 

Submodules Offline A-124 

Process Image A-20, A-21, A-22, A-23 

Updating Block Calls 10-27 

Updating Firmware 18-10 

Updating Firmware in Modules and 

Submodules Online 18-10 

Updating the Operating System (see 

Updating Firmware in Modules and 

Submodules Online) 18-10 

Updating the Operating System of Modules 

and Submodules Offline A-124 

Updating the Window Contents 18-7 

Uploaded Blocks 

Editing in the PG/PC 19-16 

Uploading 

Blocks from an S7 CPU 19-15 

Station 19-14 

Uploading from the Programmable 

Controller to the PG/PC 19-13 

Upper and Lower Case 8-16, 8-17 

Symbols 8-16, 8-17 

Upper Limits for Entering Counters 20-8 

Upper Limits for Entering Timers 20-7 

User Data A-118 

User Interface 5-22 

User Memory 19-20 

Compressing 19-20 

User Program A-16 

Downloading A-16 

in the CPU Memory A-16 

Tasks 4-1 

User Programs 

Downloading 19-3 

User Rights Through The Automation 

License Manager 2-1 

User Text Libraries 16-34 

User-Defined Data Type 


User-Defined Data Types A-51 

User-Defined Data Types (UDT) 9-12 

Entering the Structure 11-7 

User-Defined Data Types in STL Source 

Files 13-28 

Example 13-28 

User-Defined Diagnostic Messages 

Creating and Editing 16-19 

User-Defined Diagnostic Messages 


Uses for Saving/Archiving 24-5 

Using 

SFC A-20 

Using a Micro Memory Card as a Data 

Carrier 6-24 

Using Arrays to Access Data A-45 

Using Clock Memory and Timers A-128 

Using Complex Data Types A-44 

Using Foreign-Language 

Character Sets 6-5 

Using Multiple Instances 10-10 

Using Older Projects A-72, A-73 

Using Structures to Access Data A-48 

Using the Clock Functions A-126 

Using the Parameter Type ANY A-61 

Using the Parameter Type POINTER A-54 

Using the System Memory Areas A-18 

Using the Variable Declaration in Logic 

Blocks 10-6 

Using User-Defined Data Types to Access 

Data A-50 

V 

Valves 3-7 


Variable Declaration Table 10-3, 10-6, 

23-29 

FC for the Sample Industrial Blending 


for OB81 23-26 



Purpose 10-6 

System Attributes for Parameters 10-7 

Variable Declaration Window 

Index-20 


A5E00706944-01

Index 

Entering a Multiple Instance entering 

10-11 

Variable Detail View 10-8 



Copying/Moving 20-3 

Creating and Opening 20-3 

Editing 20-4 

Example 20-4, 20-5 

Example of Entering Addresses 20-9 

Inserting a Contiguous Address Range 

20-6 

Inserting Addresses or Symbols 20-4 

Maximum Size 20-6 

Saving 20-1, 20-4 

Syntax Check 20-6 

Using 20-1 

Variables 17-1, 17-2 

Modifying 20-16 

Monitoring 20-14 

Operator Control and Monitoring 17-1, 

17-2 

Version 1 Projects A-72 


Version 2 Projects A-73 


Virtual Work Memory 

Setting 26-5 

W 

Warm Restart A-5, A-6, A-7, A-8, A-9, A-10 

Abort A-5 

Automatic A-5 

Automatic without a Backup Battery A-5 

Manual A-5 

Warning A-24 



What Are the Different Messaging 

Methods? 16-1 

What You Should Know About HOLD Mode 

21-5 

What You Should Know About Micro 

Memory Cards (MMC) 6-22 

What You Should Know About Testing in 

Single-Step Mode/Breakpoints 21-3 

What You Should Know About the HOLD 

Mode 21-5 

Which Message Blocks Are Available? 

16-6 

Which Message Blocks Exist? 16-6 

WinAC 6-24 


Changing 5-31 

Restoring 5-31 

Saving 5-31 

Window Contents 18-7 

Updating 18-7 

Windows 5-37 

Toggling 5-37 

Windows Language Settings 6-6 

WinLC 6-24 

Winter time 18-9, 18-10 

WORD A-33, A-39 

Word (WORD) A-33 

Area A-33 

Work Memory 19-3, 19-4, A-15, A-16, A-17 

Working Area of a Window 5-22 

Working with Libraries 9-20 

Working with Network Templates 10-17 

Working with Version 2 Projects and 

Libraries 7-1 

WR_DPARM A-119, A-123 

WR_PARM A-119, A-123 

WR_USMSG 23-22 

Writing to a Data Block in 


Y 

Y link 23-13 


A5E00706944-01 

Index-21

Index 

Index-22 


A5E00706944-01

Simatic - Programming with STEP7 - Process Control and ...

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